In recent years, driven by the continuous and rapid expansion of the new energy vehicle market, the demand for lithium-ion power lithium batteries in my country has surged, and the market size has continued to grow rapidly. Power lithium batteries have gradually become an important engine for the expansion of the lithium battery industry.
Currently, my country's lithium battery industry is experiencing tremendous market opportunities, but it also faces numerous severe challenges. In the context of economic globalization, how to achieve sustainable development for my country's lithium battery industry, and how to further promote deeper integration and technological innovation across the industrial chain, are questions that the entire lithium battery sector must seriously consider.
In this series of articles, I will discuss with readers the technological driving forces behind the development of the lithium battery industry, the dynamics and trends of the international lithium battery industry under the background of economic globalization, and the future development model and prospects of my country's lithium battery industry. I hope to provide readers with some different perspectives and angles on the issue of sustainable development of my country's lithium battery industry.
With the widespread application and popularization of digital electronic products and power storage products, the global lithium battery market has grown rapidly over the past few decades. In recent years, driven by the continued rapid expansion of the new energy vehicle market, the demand for lithium-ion power batteries in my country has surged, and the market size has continued to grow rapidly. Power lithium batteries have gradually become an important engine for the expansion of the lithium battery industry.
Currently, my country's lithium battery industry is experiencing tremendous market opportunities, but it also faces numerous severe challenges. In the context of economic globalization, how to achieve sustainable development for my country's lithium battery industry, and how to further promote deeper integration and technological innovation across the industrial chain, are questions that the entire lithium battery sector must seriously consider.
In this series of articles, I will discuss with readers the technological driving forces behind the development of the lithium battery industry, the dynamics and trends of the international lithium battery industry under the background of economic globalization, and the future development model and prospects of my country's lithium battery industry. I hope to provide readers with some different perspectives and angles on the issue of sustainable development of my country's lithium battery industry.
The commercial success of an industrial product or new technology depends on many factors. A careful analysis of numerous successful high-tech products worldwide reveals that technology is often not the most important or decisive factor, as exemplified by Tesla electric cars. However, it's important to emphasize that this statement is incorrect if reversed. Technology is not omnipotent, but technological innovation and progress are absolutely essential!
The development of the physical manufacturing industry may be affected in the short term by factors such as capital operations, business models, and even politics. However, when measured within the context of the international industrial landscape over a longer period, such as one or two decades or even three or five decades, the manufacturing sector fundamentally relies on technological innovation and progress. The chemical power source industry is no exception. Before delving into the development direction and trends of the lithium battery industry, it is necessary to thoroughly explore and clarify the trajectory of technological progress and development in the chemical power source industry.
➤1.1 Technological Development History of the Chemical Power Source Industry
Chemical power sources are actually a very old discipline. If we start counting from the invention of the lead-acid battery by the Frenchman Planté in 1859, the battery industry has a history of 150 years. Let's first review the major technological advancements and innovations that have been milestones in the battery industry:
As we can see from the table above, technological progress in the chemical power source industry was very slow from Plant's invention of the lead-acid battery in 1859 to the 1950s. The golden age of breakthroughs in the chemical power source industry was from the 1950s to the 1990s, especially during the height of the Cold War between the US and the Soviet Union in the 1970s and 80s. The Arab-Israeli wars of the 1970s (essentially localized "hot wars" triggered by the US-Soviet rivalry) led to two international oil crises, which not only had a profound impact on the global political and economic landscape but also prompted Western countries to deeply recognize the importance of finding new energy sources, thus providing an unprecedented boost to research into new high-energy chemical power sources.
It was during this period that Europe and the United States made significant progress in fundamental research on organic electrolytes, solid electrode materials, proton exchange membranes, and electrode process kinetics. The four most important high-energy chemical power source systems today—fuel cell lithium-ion batteries (AFC and PEMFC), sodium-sulfur batteries (including Zebra batteries), nickel-metal hydride batteries, and lithium-ion batteries—were established based on their fundamental principles during this time. Although lithium-ion batteries were industrialized by Sony in 1991, just after the end of the Cold War, they are essentially a technological achievement from the 1980s, a period of intense Cold War activity.
In my personal opinion, over the past century and a half, the chemical power source industry has only experienced two truly revolutionary breakthroughs: the practical application of fuel cell lithium batteries in the 1960s and 70s and the industrialization of lithium batteries in 1991. My reasoning for considering these two high-energy chemical power source systems revolutionary is based on the following reasons:
➜ Fuel cell lithium-ion batteries, based on a unique heterogeneous electrocatalysis and open-loop operating principle, are revolutionary and groundbreaking from the perspective of electrochemical devices. Their unique operating mode allows them to simultaneously achieve higher power and energy density compared to existing rechargeable battery systems. From the perspective of electrochemical devices, fuel cell lithium-ion batteries represent a more advanced level of development compared to rechargeable batteries.
➜ Lithium-ion batteries made high-voltage, high-energy-density secondary battery systems based on organic liquid electrolytes a reality for the first time. Based on the principle of embedded reactions, lithium-ion batteries differ from the heterogeneous redox reaction mechanism commonly used in traditional secondary batteries, making them groundbreaking from the perspective of electrochemical devices. Furthermore, lithium-ion batteries broke the traditional constraint that the negative electrode must be a lithium source, which is also revolutionary in electrochemical practice.
If we look back at the past two or three decades, we can clearly see that in the quarter-century since the industrialization of lithium batteries in 1991, no entirely new high-energy chemical power source system has been commercialized in the world.
If readers are familiar with the current research progress on novel international electrochemical energy storage and conversion systems, they should understand that it is highly unlikely that a completely new high-energy chemical power source system will be commercialized within the foreseeable 5-10 years. Technological advancements in the chemical power source industry are primarily focused on further optimizing, improving, and perfecting existing chemical power source systems.
While these improvements are even more economically efficient than developing entirely new chemical power source systems from a practical application perspective, these technological advancements are not revolutionary or groundbreaking breakthroughs. In reality, the field of basic research on high-energy chemical power sources has not made any groundbreaking progress in the past quarter-century, a stark contrast to the "explosion" of high-energy chemical power source technology in the 1970s and 80s.
➤1.2 The arduous journey of technological progress in the lithium battery industry
Looking back at the technological development of lithium batteries over the past two or three decades, we can clearly see the slow and arduous progress. This article uses the industrialization process of the most representative cathode materials to illustrate this point. Table 2 compares the year several mainstream lithium-ion battery cathode materials were first publicly reported, the time of their first industrialization, and the time to large-scale commercial use. We can clearly see that the time span from initial public reporting to large-scale production and application for these mainstream cathode materials has actually become increasingly longer!
Of course, many people may not be psychologically able to accept that the large-scale commercial application of lithium iron phosphate (LFP), the cathode material most "familiar" to Chinese consumers, wouldn't be until 2014. However, according to statistics from the Gaogong Lithium Battery Industry Research Institute (GBII), the actual sales volume of LFP in China did not reach a commercial scale of 5,000 tons/year until 2013. Therefore, more and more lithium battery professionals agree that the first year of commercial application of LFP should actually be counted as 2014. As for the lithium-rich manganese-based solid solution cathode material (OLO) from Argonne National Laboratory (ANL) in the United States, which has been hyped up in recent years, there is still no sign of industrialization.
Because the performance and cost of lithium batteries largely depend on the cathode material, cathode materials represent the area with the largest R&D investment and the fastest progress among the four fundamental materials for lithium batteries. In contrast, the technological advancements in anode materials are much slower.
The use of graphite as a lithium-ion anode material was first reported by French scientist Yazami in 1983. However, after Osaka Gas Company in Japan industrialized MCMB (Multi-Metal Block Cell) in 1994, the performance of lithium-ion batteries improved significantly, allowing them to rapidly capture the mobile phone battery market and experience rapid development. Subsequently, modified natural graphite was widely used in small 3C batteries, and since 2005, artificial graphite, with its excellent electrochemical properties, has begun to be widely used in power lithium-ion batteries.
Currently, graphite-based materials still hold 99% of the global lithium-ion battery anode market share. Other emerging anode materials, such as LTO, hard carbon, and silicon-carbon composite anode materials, are only just beginning to see small-scale applications, and these new anode materials are unlikely to replace the monopoly of graphite anode materials. Compared to cathode and anode materials, technological progress in electrolytes and diaphragms is also very slow.
As for lithium battery manufacturing processes, the basic manufacturing process for liquid batteries is still not much different from what Sony used 20 years ago, while the mainstream technology for polymer batteries (non-pouch lithium batteries) is still based on improvements made by Bellcore in the United States.
Battery technology itself is not inherently complex; its basic principle is still the same as the voltaic pile, which involves a redox reaction. However, simple principles do not equate to easily improved performance, as a battery system is a complex, multivariable system. Although the battery principle is simple, achieving revolutionary breakthroughs in performance improvement is extremely difficult. Solving a series of scientific and engineering problems involves numerous interdisciplinary issues, including electrochemistry, interface chemistry, crystal chemistry, thermodynamics/kinetics, solid-state physics, electrical engineering, and mechanical design.
If you open the back cover of the latest iPhone and iPad, you'll see that the motherboard circuitry is getting smaller and smaller, while the battery takes up most of the space. Given the current state of battery technology, this awkward situation is likely to continue for many years to come.
To be realistic, the progress of lithium batteries and other high-energy chemical power sources has been very slow over the past two decades, with the pace of technological advancement and innovation falling far short of expectations. As a result, many experts have been proven wrong by their confident technological predictions, and many ambitious investors and entrepreneurs have made poor decisions!
➤1.3 A Rational View of the Current Lithium Battery Research "Boom"
Of course, some readers might say that I'm spreading "negative energy." For example, don't we often see news reports about a university developing a revolutionary "new material" that can increase battery capacity by many times? Or a company developing a new battery technology that allows an electric car to travel XXX kilometers on a single charge? In recent years, we've seen similar news almost every month. Personally, I believe we should view the current "boom" in lithium battery research rationally.
Since Sony Corporation of Japan first successfully commercialized lithium batteries in 1991, the performance of lithium batteries has been greatly improved, enabling them to quickly occupy the mobile phone battery market and develop rapidly. At the end of the last century, the first wave of lithium battery industrialization was launched globally, corresponding to the first wave of international lithium battery basic research from 1996 to 2002.
The first wave of lithium battery research yielded extremely fruitful results. Most of the electrode materials currently used in commercial applications, such as ternary materials, lithium iron phosphate, hard carbon, and lithium titanate, were discovered and reported during this period. Even the currently popular lithium-rich manganese-based solid solution cathode and silicon-carbon composite anode materials were first reported during this period.
The Clinton administration in the United States launched basic research and industrialization of the hydrogen economy (hydrogen energy and lithium-ion fuel cells) in 1996, with the European Union following closely behind. During President George W. Bush's eight years in office, research on the "hydrogen economy" reached its peak in developed Western countries, especially the United States. In contrast, basic research on lithium-ion batteries experienced a slump from 2002 to 2007, although the industrialization of lithium-ion batteries continued to develop rapidly.
The second wave of research and industrialization of fuel cell lithium batteries gradually cooled down after 2007. Since Obama was elected President of the United States in 2008, the US government has shifted its strategic focus on electric vehicles from hydrogen energy and fuel cell lithium batteries to lithium batteries, which is the current second wave of international lithium battery research and industrialization.
Many researchers involved in fundamental or industrial technology development of lithium batteries have already noticed a geometric increase in SCI papers related to lithium batteries internationally since 2008. According to Web of Science search results, nearly 10,000 SCI papers related to lithium batteries were published in 2016 alone, more than the total number of SCI papers published in the ten years prior to 2006!
Judging solely from the number of SCI papers, the recent years have seen an unusually active "lithium battery research" field, seemingly indicating that the next technological breakthrough is imminent. However, the situation is not as simple as it appears. A careful examination of the annual reports from the DOE (BATT and ABR projects), the EU's ALISTORE project, and Japan's NEDO—these are some of the world's most prestigious international government research projects on lithium batteries. It becomes clear that compared to the fruitful first wave of lithium battery research at the end of the last century, this round of fundamental research has yielded virtually no breakthroughs. Instead, it exhibits a clear characteristic of academic "bubble-like" development, particularly in the areas of "nano-lithium batteries" and lithium iron phosphate.
These two fields account for over 70% of the total number of SCI papers, which is commonly referred to as "padded" SCI papers. Regarding these unhealthy practices in the lithium battery academic community, several leading lithium battery researchers, including JB Goodenough, JRDahn, and M. Armand, have repeatedly offered sharp criticisms at numerous international academic conferences.
In fact, I have always believed that the industry, rather than academia, is the main force behind the second wave of international lithium battery research, because lithium battery is a typical applied discipline and the lithium battery industry has been commercialized for over 25 years. Therefore, the changes in the themes and number of patents published annually in the lithium battery field can basically reflect the technological innovation enthusiasm and development trends of the international lithium battery industry.
International patent searching and analysis in the field of lithium battery materials has been one of my areas of expertise for many years. My statistics show that the number of international lithium battery-related patents peaked in 2015, and the number of new patents continued to decline each year in 2016 and 2017. There is generally a two-year lag between patent application and publication, meaning that the international lithium battery industry actually experienced a reversal in technological development as early as 2013, coinciding with the bankruptcy of A123 in the United States. Is this point in time merely a coincidence? I will analyze this in detail in later chapters.
Since this round of basic lithium battery research has not yielded any breakthroughs so far, it's only a matter of time before the DOE shifts its funding focus to high-energy electrochemical power sources. After President Trump took office, he drastically cut research budgets for lithium batteries, eliminating the ARPA-E project entirely and significantly reducing DOE funding. In my opinion, this is actually an overcorrection to the bubble-like nature of the second wave of lithium battery research. Meanwhile, the European Union (EU) quietly shifted its research focus back to hydrogen energy and fuel cell lithium batteries in the second half of 2016.
In fact, the US DOE's technology roadmap and development goals have always been a fundamental reference for my country's Ministry of Science and Technology and Ministry of Industry and Information Technology in formulating research and industrialization policies related to new energy vehicles. So, in which areas will the DOE shift its focus in the next round of research and industrialization of novel high-energy chemical power sources? Let's wait and see.
➤1.4 The underlying reasons for the slowdown in the development of global chemical power source technology
So, a very real question arises: why has the pace of breakthrough innovation in high-energy chemical power source technology slowed significantly, or even stagnated, compared to the 1970s and 80s, over the past two decades? In my personal opinion, the key reasons may lie in the following two aspects:
➜ Major advancements in science and technology always involve a process of quantitative and qualitative change. The qualitative leap brought about by a major technological revolution greatly propels society forward, but it also consumes the large amount of accumulated, albeit smaller, quantitative changes. Therefore, progress will be slower for a considerable period. This is a simple yet profound truth. Of course, this doesn't mean that technological progress will immediately stop; technology is still advancing, but the pace of advancement will slow.
In other words, global science and technology may be entering a period of "stagnation in growth," and this period could very well be quite long. Tyler Cowen, a professor of economics at George Mason University, wrote a book called *The Great Stagnation*, which offers a profound analysis of the impact of the slowdown in global scientific and technological progress on the US economy and society.
The reason why ordinary people feel that technological development is getting faster and faster is partly due to the "lag effect," and partly because the rapid rise of IT, communication, and network technologies in the 1980s and 1990s masked the stagnation in technological progress in other fields. Many modern high-tech products, such as mobile phones, had prototypes that existed half a century ago, but they remained a luxury item. Only after the supporting technological level in other sectors (microelectronics) caught up, coupled with innovations in commercial organization and marketing, did mobile phones become widely available.
But for ordinary people who use smartphones, high technology feels so close to them! However, most physical manufacturing sectors, including the chemical power industry, have experienced a "stagnation of technological revolution" over the past one or two decades.
➜The current relative stagnation in technological development is, in my personal opinion, largely due to the end of the Cold War and the collapse of the Soviet Union. The 20th century saw two golden ages of technological advancement: one in the 1930s and 40s before and during World War II, and the other in the 1970s and 80s during the height of the Cold War.
The latter, in particular, represents a period of explosive growth in human high technology. Specifically, the development of high-energy chemical power sources in the 1960s and 70s was propelled by the US-Soviet space race, which spurred the practical application of fuel cell lithium-ion batteries (AFC) and high-voltage nickel-metal hydride batteries. The demand for high-energy chemical power sources in various electronic devices further spurred the industrialization of sodium-sulfur batteries, atmospheric-pressure nickel-metal hydride batteries, and primary/secondary lithium-ion batteries.
I am not advocating war, but realistically speaking, the demand for aerospace technology drives high technology in a way that far surpasses that of civilian applications. Technological development often involves trial and error, and the discovery of many major fundamental disciplines requires astronomical amounts of human, material, and financial resources, which only a state apparatus can accomplish.
In the civilian sector, profits and economic benefits are prioritized. Based on past experience, the practical applications of high-tech innovations in purely civilian settings are actually quite limited. A good example in the field of chemical power sources is the proton exchange membrane fuel cell (PEMFC). The initial rapid development of PEMFCs was inseparable from the substantial and continuous R&D funding support provided by the Canadian government to Ballard in the 1980s and 90s.
Over the past two decades, dozens of navies worldwide have deployed PEMFC-powered AIP systems, demonstrating the high level of technological maturity and reliability of PEMFCs. However, the commercialization of fuel cell electric vehicles has been slow over the past few decades. Industry experts now generally believe that the commercialization of fuel cell electric vehicles is just around the corner, and Japanese companies like Toyota and Honda, as well as American companies like GM, have already begun small-scale commercial production of fuel cell electric vehicles.
However, in my personal opinion, large-scale commercialization of fuel cell-powered lithium-ion battery electric vehicles remains unrealistic for the next few decades. The reasons for this are multifaceted (see the related article "Discussion on Power Sources for Pure Electric Vehicles: Lithium Batteries VS Fuel Cell-Powered Lithium Batteries" in *High-Tech Lithium Battery* for details), including technological bottlenecks, but more importantly, economic considerations. One of the most significant reasons is the current lack of strong national impetus for this development in Europe and the United States.
If we can consider these two aspects together, we will understand why the lithium battery industry has not seen a revolutionary breakthrough in the past two decades, and why no entirely new high-energy chemical power source system has been commercialized worldwide. The lithium battery industry is a capital- and technology-intensive high-tech industry, belonging to the typical real economy. Therefore, technological progress in the lithium battery field with industrial significance remains very slow, and it is extremely difficult to solve a series of scientific and engineering problems and achieve revolutionary breakthroughs.
Does understanding this phenomenon relate to our understanding of the development trend of lithium batteries? Yes, and the relationship is extremely important. This is because my subsequent analysis of the international lithium battery industry development trend and landscape is based on the objective law of a global slowdown or even relative stagnation in technological development.
➤1.5 A dialectical view of the slowdown in the development of global chemical power source technology
As I pointed out in my previous analysis, from the perspective of technological innovation and progress, the international chemical power source industry is currently in a stage of quantitative change, and the tipping point for qualitative change cannot be foreseen. Technological development is always a slow process of quantitative change. Leading companies or countries always need to invest a lot of money (in terms of qualitative change) to make slow progress (because scientific research involves a lot of trial and error for explorers), while followers can invest less money to follow the path of the leaders. Because there are no trial and error issues, their catch-up speed will be higher than that of the leaders. This is the so-called "latecomer advantage".
At this stage, latecomers continuously gain the right direction and technology, rather than the lessons learned from the failures of pioneers. In this situation, latecomers (countries or companies) have a real chance to fully utilize their late-mover advantage and participate in the next technological revolution in a position as advantageous as that of pioneers, thus leaping to become technologically advanced countries or companies.
Of course, there are prerequisites for developing countries or companies to catch up by leveraging their late-mover advantage. In my personal opinion, two prerequisites are crucial: one is choosing the right target (country or company) to catch up with, and the other is choosing the right direction for selective breakthroughs.
In fact, if we compare the development trajectories of the lithium battery industries in my country and South Korea, readers will clearly understand why these two prerequisites are so crucial. This topic will be discussed in more detail in later chapters.
➤1.6 Technological Development Trends in the High-Energy Chemical Power Source Industry
Battery technology itself is not inherently complex; its basic principle is still the voltaic pile, which is essentially a redox reaction. However, simple principles do not equate to easily improved performance, as a battery system is a complex, multivariable system. Discussing the technological development trends and directions of the high-energy chemical power source industry involves the integration of multiple disciplines and belongs to a highly specialized high-tech field. Here, I will set aside the profound scientific principles of electrochemistry, solid-state chemistry, and electrocatalysis, and instead discuss the technological development trends of the high-energy chemical power source industry from a macro perspective, offering a clear and accessible overview.
First, we need to consider a fundamental question: what is the fundamental direction of development for rechargeable batteries? If we compare the energy density of various commercial rechargeable batteries over the past 150 years, we will clearly see this increasing trend, along with an exponential increase in cycle performance. Among these, the improvement in energy density is the fundamental indicator. Then, readers should be able to understand the fundamental reason why lithium batteries have experienced continuous expansion and rapid development in the application market over the past two decades, in contrast to the current industry difficulties faced by nickel-metal hydride batteries.
The reasoning is simple: among all commercially available rechargeable battery systems, lithium batteries not only have the highest energy density but also boast an ultra-long cycle life. Other technical specifications, such as rate capability and temperature performance, are not the core issues.
So, could other new chemical power source systems replace existing lithium battery systems in the future? In fact, secondary batteries essentially use charged ions (H+, Li+, Na+, Al3+, Zn2+, etc.) as energy storage carriers. The charge-to-mass ratio (Q/M) of these ions, to some extent, determines the theoretical energy density of the battery system. Among these ions, H+ has the highest charge-to-mass ratio (1.0), followed by Li+ (0.144), Al3+ (0.111), Mg2+ (0.083), and Na+ (0.0455).
Therefore, from this perspective, the specific energy of chemical power sources is finite, limited by the system's theoretical capacity and operating voltage, and cannot follow Mohr's Law. Lithium has the most negative standard electrode potential and the second-highest theoretical specific capacity among known metals, making lithium-ion batteries the highest in theoretical energy density among all secondary battery systems. Therefore, high-energy secondary batteries in non-aqueous systems will inevitably be primarily lithium-ion batteries, supplemented by other electrochemical systems (sodium-ion, magnesium-ion, etc.). So, a question many readers are concerned about is: in what direction will lithium-ion secondary batteries develop?
From an electrochemical perspective, existing lithium batteries can only be considered "half" high-energy batteries, because their high specific energy is mainly based on the extremely low electrode potential of the negative electrode. The current transition metal oxide cathode materials are not much different from the cathode materials of aqueous secondary batteries in terms of both operating voltage and specific capacity.
Therefore, to make lithium-ion batteries truly high-energy batteries, there are only two paths: increase the battery's operating voltage or increase the specific capacity of the positive and negative electrode materials. Since the negative electrode's operating voltage cannot be reduced further, the high voltage must be applied to the positive electrode material. 5V nickel-manganese spinel, due to its low capacity, cannot effectively improve the battery's energy density.
Currently, the actual capacity of lithium-rich manganese-based solid solutions (OLO) can reach 250 mAh/g, which is very close to the theoretical capacity of layered transition metal oxide cathodes. The specific capacity of Si/C composite anode materials and silicon-based alloy anode materials has reached 600-800 mAh/g, and this capacity range is actually the limit for practical application (suppressing volume change).
If OLO is paired with a high-capacity silicon-based anode, the energy density can reach 350Wh/Kg. However, the combination of a high-nickel NMC cathode and a Si/C composite anode material, which has greater practical application value, achieves an actual energy density slightly above 300Wh/Kg. This energy density is almost the limit for practical conventional liquid lithium batteries.
To further improve the specific energy of lithium batteries, it is necessary to break free from the constraints of the current intercalation reaction mechanism and adopt a heterogeneous redox mechanism, similar to other conventional chemical power sources, that is, to use metallic lithium as the negative electrode. However, lithium dendrites are prone to causing short circuits, and the strong reaction between highly active dendrites and liquid organic electrolytes brings the problem back to the starting point of lithium batteries.
The fundamental reason why lithium-ion batteries use graphite anodes is that graphite lithium intercalation compounds (GICs) prevent the formation of lithium dendrites, and the reduced reactivity of lithium metal by GICs makes a stable SEI interface possible. Therefore, lithium-ion batteries based on intercalation reactions are actually a compromise made out of necessity!
So is there any way to solve the problem of lithium metal? Theoretically, using solid/polymer electrolytes or adding inorganic additives to liquid electrolytes could alleviate the lithium dendrite problem, but in the actual production and use of battery cells, there will be many technical difficulties, which will limit the space for further improvement of operating voltage.
In my personal opinion, only all-solid-state lithium-ion batteries using inorganic solid electrolytes can make the industrialization of high-energy (high-voltage) rechargeable battery systems based on lithium metal anodes possible. Toyota is a global leader in all-solid-state batteries, with nearly 20 years of R&D experience in this field. Currently, its prototype batteries are significantly more advanced than those of other companies and research institutions. All-solid-state rechargeable batteries using lithium metal anodes are naturally the "ultimate lithium battery," and their industrialization is extremely difficult. In my view, if all-solid-state lithium-ion batteries based on lithium metal anodes can be industrialized in the future, it will be a revolutionary breakthrough comparable to the industrialization of conventional liquid electrolyte lithium-ion batteries.
Why don't I believe that the currently popular lithium-sulfur and lithium-air batteries are the next breakthrough for lithium batteries? Actually, Li-S and Li-Air batteries are outdated systems; they've just been repackaged and hyped up in recent years. Research on the sulfur cathode has led to two directions: one is high-temperature Na-S batteries (NGK in Japan has decades of industrial-scale experience in this area), and the other is the currently popular room-temperature Li-S batteries.
Currently, Li-S batteries still face numerous technical challenges and have not yet met the requirements for industrialization. Due to the unique "polysulfide ion shuttle effect" of Li-S batteries, I do not believe that Li-S batteries will achieve widespread commercial application, except in some niche or special application areas.
Li-Air batteries fall under the category of air batteries. Readers with some electrochemistry background should understand that to significantly increase the energy density of existing electrochemical systems, it's necessary to utilize oxygen from the air as an oxidant, since oxygen is theoretically not included in the weight of the electrode active material. Following this line of thought, various metal-air batteries have been developed. The primary zinc-air battery is relatively mature, while the secondary Li-Air battery is currently the most researched.
However, in my personal opinion, metal-air batteries, especially rechargeable metal-air batteries, actually combine the disadvantages of both rechargeable batteries and fuel cell lithium batteries, and amplify those disadvantages. Therefore, rechargeable Li-Air batteries simply do not have the potential for industrialization. Due to space limitations, I will not elaborate on the scientific reasons here. For example, IBM invested heavily and spent years researching lithium-air batteries, only to find the project tragically canceled.
The reason I believe that all-solid-state lithium batteries will be a revolutionary breakthrough after conventional liquid lithium batteries is that, on the one hand, their energy density will be greatly improved, and on the other hand, all-solid-state lithium batteries will create a high technological barrier in production technology.
What is technological innovation? Simply put, technological innovation is when the technology is highly complex and cannot be easily copied by competitors. Li-S batteries clearly lack this fundamental characteristic. All-solid-state lithium batteries require battery manufacturers to possess considerable R&D and technological capabilities. This is because both the positive and negative electrodes require coating technology, and the production of the solid electrolyte must also be completed by the cell manufacturer itself. This completely overturns the current model where battery manufacturers can purchase all electrode raw materials on the market and only handle cell production.
More importantly, the manufacturing process and technology of all-solid-state batteries are completely different from those of conventional liquid lithium batteries. All of this presents a significant technological barrier to the industrialization of all-solid-state batteries. This high technological barrier is precisely what is necessary for a revolutionary breakthrough in chemical power sources; otherwise, can it still be called a "revolutionary breakthrough"?
However, I would like to emphasize that due to the slow ion transport rate in solid electrolytes and the high resistance at the interface between solid electrolytes and positive and negative electrode materials, these two fundamental characteristics determine that the rate performance of all-solid-state batteries is inevitably their weakness, and the cycle performance and temperature performance of all-solid-state batteries will also face great challenges.
Therefore, I personally believe that all-solid-state lithium batteries may find practical application in small 3C electronic devices in the future, but large-scale power lithium batteries may not be their main application area. Based on the characteristics of all-solid-state batteries, they will be an important supplement to conventional liquid lithium batteries, and are unlikely to replace liquid lithium batteries as the mainstream direction for lithium battery commercialization. According to the current international research and industrialization status of all-solid-state lithium batteries (Japan is in a leading position in this field, while my country's research in this area is relatively weak), I do not believe that all-solid-state lithium batteries have the possibility of large-scale commercialization within the next 5-10 years.
The energy density of rechargeable batteries definitely has an upper limit and cannot follow Moore's Law. Simply put, this is determined by the sealed operating method of rechargeable batteries. Rechargeable batteries must evolve towards fully sealed systems to achieve maintenance-free operation (this is crucial for lithium batteries), and it is precisely because a rechargeable battery is a sealed system that its energy density cannot be very high. Otherwise, what's the difference between a sealed high-energy system and a bomb? It doesn't make sense from the most basic law of conservation of energy! Therefore, to obtain higher energy density, an open operating principle must be adopted, such as metal-air batteries (semi-fuel lithium batteries) and fuel cell lithium batteries.
笔者前面分析过，金属空气电池由于一些最基本技术限制，决定了不可能大规模应用。因此，从高能化学电源的最根本需求(追求更高能量密度)而言，燃料动力锂电池必然还会有下一轮的研究和产业化热潮，因为到目前为止没有任何一种二次电池体系在能量密度和功率密度上可以跟PEMFC相提并论，这个根本特点决定了PEMFC的发展后劲。
燃料动力锂电池独特的异相电催化反应过程，使得不管是氢的电化学氧化还是氧的电化学还原，都可以在Pt/C催化剂表面获得较高的交换电流密度。而PEMFC的能量密度则取决于储氢系统的储氢量，同样也可以通过新增储氢罐体积或者数量而获得提升。
也就是说，PEMFC系统可以同时兼具高能量密度和高功率密度，这一本征特点特点则是任何一种二次电池都不可能具备的，其根本原因在于封闭体系和开放式工作方式的本质差别。而同时兼具高能量和高功率的工况特性，恰恰是现代汽车对动力系统的最基本技术要求。站在电化学器件的角度，相较于二次电池，燃料动力锂电池是化学电源的一个更高的发展层次。
从根本上而言，二次电池是一个能量存储装置，通过可逆的电化学反应实现电能的存储和释放。而燃料动力锂电池则是一个电能生产装置，它通过电催化反应将燃料中的化学能转换成电能释放出来，工作方式跟内燃机比较类似。燃料动力锂电池和二次电池在工作方式上的本质性不同，决定了二次电池适用于中小功率的储能用途，而燃料动力锂电池则适合较大功率的应用。
实事求是而言，锂电池当前的产业和技术成熟度远高于燃料动力锂电池，这也是我国政府目前大力发展锂电池纯电动汽车的重要原因，而欧美日则是将燃料动力锂电池技术作为未来纯电动汽车的战略发展方向。
简而言之，笔者个人认为高能化学电源产业的下一个创新性突破点有可能是全固态锂电池的产业化和PEMFC燃料动力锂电池的大规模商业化。就这两个领域当前的研究和产业化进展而言，笔者个人认为至少要5-10年的时间才有可能实现。
