Since the industrialization of lithium-ion batteries in 1991, graphite has dominated the market as the anode material. Lithium titanate, as a novel anode material for lithium-ion batteries, began to gain attention in the late 1990s due to its numerous superior properties. For example, lithium titanate maintains high crystal stability during the insertion and extraction of lithium ions, with minimal change in lattice constant (volume change).
This "zero-strain" electrode material significantly extends the cycle life of lithium titanate batteries. Lithium titanate possesses the unique three-dimensional lithium-ion diffusion channels characteristic of its spinel structure, resulting in excellent power characteristics and superior high and low temperature performance. Compared to carbon anode materials, lithium titanate has a higher potential (1.55V higher than that of metallic lithium), which means that the solid-liquid layer that typically grows on the electrolyte and carbon anode surfaces essentially does not form on the lithium titanate surface.
More importantly, lithium dendrites are difficult to form on the surface of lithium titanate within the normal operating voltage range. This largely eliminates the possibility of short circuits caused by lithium dendrites inside the battery. Therefore, lithium-ion batteries with lithium titanate as the negative electrode are the safest among all types of lithium-ion batteries that I have seen so far.
Most industry insiders have heard that lithium batteries using lithium titanate instead of graphite as the negative electrode material can have a cycle life of tens of thousands of cycles, far exceeding that of common traditional lithium-ion batteries, which only last for a few thousand cycles before reaching the end of their lifespan.
Because most professionals in the lithium battery industry have never actually built lithium titanate battery products, or have only tried a few times before giving up after encountering difficulties, they haven't been able to calmly and carefully consider why most perfectly crafted traditional lithium-ion batteries typically only achieve a lifespan of 1000 to 2000 charge-discharge cycles.
Is the short cycle life of traditional lithium-ion batteries due to the inability of one of its basic components—the graphite anode—to withstand heavy loads? Once the graphite anode is replaced with a spinel-type lithium titanate anode, the essentially the same lithium-ion battery chemical system can cycle for tens of thousands or even hundreds of thousands of times.
Furthermore, while many people enthusiastically discuss the relatively low energy density of lithium titanate batteries, they overlook a simple yet crucial fact: the ultra-long cycle life, exceptional safety, excellent power characteristics, and good economic efficiency of lithium titanate batteries. These characteristics will be the cornerstones for the currently emerging large-scale lithium battery energy storage industry.
Over the past decade or so, research on lithium titanate battery technology has surged both domestically and internationally. Its industrial chain can be divided into lithium titanate material preparation, lithium titanate battery production, lithium titanate battery system integration, and its application in the electric vehicle and energy storage markets.
1. Lithium titanate materials
Internationally, leading companies in the research and industrialization of lithium titanate materials include Altair Nanotechnology (USA), Ishihara Sangyo Co., Ltd. (Japan), and Johnson Matthey (UK). Altair's lithium titanate materials exhibit superior performance in terms of rate capability, safety, long lifespan, and high and low temperature performance. However, the lengthy and complex production process results in high production costs, making commercialization more challenging.
Ishihara Sangyo is one of Asia's largest titanium dioxide manufacturers, with production bases in Japan and Singapore. Leveraging its abundant raw material resources, Ishihara has successfully developed a variety of low-cost, high-rate lithium titanate products with different particle sizes using a wet process. Its products with similar performance have a significant price advantage compared to Altair's lithium titanate materials, but are slightly inferior to products from domestic Chinese companies. Johnson Matthey acquired lithium iron phosphate and other materials from the former Süd Chemie AG, but its investment in the research and development and production of lithium titanate materials has been insufficient, resulting in inconsistent product quality.
There are already several domestic companies producing lithium titanate materials in large quantities, such as Sichuan Xingneng New Materials Co., Ltd., Zhuhai Yinlong New Energy Co., Ltd., Huzhou Microvast Power Co., Ltd., Shenzhen BTR New Energy Materials Co., Ltd., Hunan Shanshan New Materials Co., Ltd., as well as several smaller lithium titanate manufacturers in Anhui and the surrounding areas of Shenzhen.
Sichuan Xingneng is a professional manufacturer of lithium titanate materials, with an annual production capacity of 3,000 tons. Its lithium titanate production process is adaptable and stable, allowing for flexible adjustments without altering existing production lines and equipment to produce lithium titanate suitable for different customer requirements while maintaining stable product technical specifications. Leveraging upstream lithium and titanium ore resources, Xingneng achieves coordinated production from raw ore to final material, thereby improving lithium titanate product performance and reducing costs, while mitigating the impact of raw material market fluctuations.
In 2011, Zhuhai Yinlong completed the acquisition of 53.6% of the equity of Altair Nanotech Inc. of the United States, thus becoming one of the few domestic companies that simultaneously possesses multiple core technologies and more than 30 patents in applications such as lithium titanate material preparation, battery production, lithium titanate electric vehicles, energy storage systems, frequency regulation and peak shaving.
Currently, North Aotai Nanotechnology Co., Ltd. (hereinafter referred to as "North Aotai") has an annual production capacity of 100 tons of lithium titanate materials and provides high-quality nano-grade lithium titanate to both North Aotai and Zhuhai Yinlong. Zhuhai Yinlong New Energy has also established a strategic partnership with Ishihara Sangyo on the research and development of new lithium titanate materials. The cost of the material will decrease as its production volume increases, and it is expected to approach the current cost price of graphite anode materials in the next few years.
Huzhou Microvast is one of the most successful companies in China in promoting lithium titanate battery technology and other fast-charging batteries.
The lithium titanate materials produced by Huzhou Microvast are mainly used in its own lithium titanate battery products. The expanding market share of Huzhou Microvast's lithium titanate batteries both domestically and internationally has also served as a good example for the application of lithium titanate technology in the electric vehicle and energy storage markets.
Shenzhen BTR is currently the world's largest supplier of carbon anodes for lithium-ion batteries. The company boasts a strong R&D team and is one of the drafters of industry standards for lithium titanate. BTR's extensive sales network gives it a significant advantage in the lithium titanate market, having already launched two products: carbon-coated lithium titanate and carbon-free lithium titanate. However, lithium titanate is not currently BTR's core product. With the lithium titanate battery market not yet fully developed, the company has not yet formulated long-term plans for the production of lithium titanate materials.
2. Lithium titanate batteries and their applications in electric vehicles and energy storage
There are only a few manufacturers internationally capable of mass-producing lithium titanate batteries, primarily Altair (USA) and Toshiba (Japan). The main application markets for lithium titanate batteries are electric vehicles, energy storage, and industrial applications.
Altair, an American company, possesses unique core technologies in lithium titanate battery manufacturing and remains a leader in large-scale lithium titanate battery production internationally, having already solved the so-called "gas" problem. Currently, its fourth-generation 65Ah single-cell lithium titanate battery is used in energy storage systems, showing no significant capacity decay even after tens of thousands of cycles at 65°C.
In the application of lithium titanate battery systems, Altair's hybrid electric buses supplied to California, USA, have been in operation since 2008. Their fuel economy of 106.4 kg/L is significantly higher than that of ordinary diesel generators (23.8 kg/L). The company also provided a 1MW storage system for the Hawaii Natural Energy Institute's 10.5MW wind farm, integrating it with the local grid and offering three years of technical support. This lithium titanate battery energy storage system is primarily used to regulate voltage fluctuations in renewable energy sources and control the unit's load variation rate to within 1MW/min.
Altair's 1MW high-capacity, high-power energy storage unit is currently the only high-capacity lithium titanate battery product in the US power grid that has passed more than two years of field commercial operation and performance quality testing. The energy storage system has more than 500,000 cycles, a total charge-discharge capacity of more than 3,300MWh, a system capacity loss of less than 2%, and no significant power degradation.
Toshiba of Japan mass-produces lithium titanate batteries under the "SCiB" brand. The 3.2Ah, 10Ah, and 20Ah aluminum-cased prismatic batteries are primarily used in electric motorcycles, electric vehicles, and automotive start-stop batteries. SCiB batteries offer advantages such as fast charging and long lifespan; they can be charged to over 90% in just 10 minutes, and their capacity decreases by less than 10% after 3000 charge-discharge cycles. They are already being used in the "EV-neo" electric motorcycle.
In the energy storage sector, Toshiba is leveraging Japan's New Sunshine Project to apply lithium titanate batteries to large-scale energy storage power stations and home energy storage systems. Another Japanese company, Murata, has developed a new type of lithium titanate battery using 5V nickel-manganese lithium oxide as the cathode. Its voltage differential is 3.2V, and its energy density can reach 130Wh/K, exceeding the current level of lithium iron phosphate batteries.
There are already several domestic manufacturers of lithium titanate batteries, such as Huzhou Microvast, Zhuhai Yinlong, Shenzhen Boleda, Tianjin Jiewei Power Industry Co., Ltd., Sichuan Xingneng, CITIC Guoan Mengguli Power Technology Co., Ltd., Hunan Shanshan, and many smaller lithium titanate battery manufacturers in Anhui and the surrounding areas of Shenzhen.
Since its establishment in 2006, Huzhou Microvast has been committed to the development of lithium titanate technology. The company has vertically integrated the lithium titanate materials, separators, electrolytes, and cathode materials required for its lithium titanate battery production. In recent years, to adapt to market demand, Huzhou Microvast has achieved a daily production capacity of 80,000 10Ah lithium titanate batteries and twice that capacity for ternary cathode lithium batteries.
By the end of 2014, Huzhou Microvast's 10-minute fast-charging battery system had been installed in over 3,000 electric buses, primarily hybrid vehicles, mainly sold to the UK, the Netherlands, and Chongqing, China. In the energy storage market, Huzhou Microvast installed lithium titanate battery energy storage systems for grid frequency regulation and demand management in Vermont, USA, and Chongqing, China.
Zhuhai Yinlong currently mass-produces 20Ah and 65Ah pouch batteries, as well as 25Ah, 30Ah, and 55Ah cylindrical batteries. Their performance indicators have reached those of lithium titanate batteries manufactured by Altair in the United States. The batteries have a cycle life exceeding 16,000 cycles with 100% DOD and 1.6 million cycles with 10% DOD. All of these batteries have passed third-party testing by the Northern Automotive Quality Supervision and Inspection Institute (Institute 201).
In terms of application, Yinlong's new pure electric buses use cylindrical, long-life, and fast-charging-discharging lithium titanate batteries, achieving a range of 30-80km. Fast charging takes only 6-10 minutes, and they can also be fully charged in 30-60 minutes using off-peak electricity rates. This series of vehicles has been successfully deployed in public transportation systems in Zhanjiang, Guangdong; Handan, Hebei; and Shijiazhuang.
Yinlong's antique-style tram, designed and developed specifically for Beijing's public transportation, began commercial operation in September 2014. This tram was also designated as the official vehicle for the Beijing APEC meeting. In the energy storage market, Yinlong has partnered with State Grid and China Southern Power Grid on national 863 projects related to energy storage, providing modules, battery box designs, and system solutions for two 2MWh and one 600kWh lithium titanate systems for the Zhangbei wind-solar-storage-transmission demonstration station and the Shenzhen Baoqing battery energy storage station, respectively.
Shenzhen Boleda has developed a unique material processing method to prepare high-performance Li4Ti5O12 materials. Through technological breakthroughs, starting with improvements in the production process of lithium titanate batteries, significant progress has been made in the design and preparation of high-performance Li4Ti5O12. Currently, mass-produced products include 17Ah, 20Ah, and 25Ah cylindrical batteries. This has solved the problem of easy gas expansion in lithium titanate batteries, resulting in high-performance lithium titanate battery products and obtaining authoritative third-party testing reports.
Starting with the design of high-power Li4Ti5O12 electrode materials, Boleda has made significant breakthroughs in the large-scale application of Li4Ti5O12 electrode materials by studying the interfacial side reactions of Li4Ti5O12 materials, revealing the gas generation mechanism and solution mechanism.
Tianjin Jiewei has obtained lithium titanate battery production technology transfer from Altair in the United States and combined it with its own years of technical accumulation in polymer soft-pack power battery production to create a unique competitive advantage. The company has successfully overcome the gas expansion problem and has the technology and capability to mass-produce large-size single-cell lithium titanate batteries with a capacity of 60Ah and a cumulative shipment of 20 million Ah.
This battery can withstand continuous charge and discharge at a rate of 10C or higher, has a lifespan of over 20,000 cycles, and a temperature range of -40 to 60°C. It is mainly used in fast-charging buses and frequency-regulating energy storage power stations.
Challenges and Future Development Direction of Lithium Titanate Battery Technology
1. Reasons for developing lithium titanate battery technology in China
Lithium titanate battery technology should have a significant advantage in the competition among various energy storage batteries in my country. In terms of lifespan alone, the ultra-long cycle life of lithium titanate batteries far surpasses that of various lead-acid batteries; its efficiency, cost, and electrochemical performance are also superior to sodium-sulfur and flow vanadium battery systems.
Historically, the main market for lithium battery products has been portable electronic devices such as mobile phones and laptops. While China consumes a large volume of mobile phones and laptops, most are not domestic brands. Therefore, domestic lithium battery manufacturers lag behind Japanese and Korean products in sales of lithium batteries for portable electronic devices.
However, the target markets for lithium titanate technology are hybrid electric vehicles, specialized industrial applications, and energy storage applications such as frequency regulation and grid voltage support. These markets are still in their early stages globally, and it remains to be seen who will dominate them. Lithium titanate technology has the potential to become a leader in these markets.
China's population accounts for approximately one-fifth of the world's total. Due to its large population, China's electric vehicle, energy storage, and industrial application markets are enormous and highly coveted by multinational corporations from many countries. In recent years, the Chinese government has attached great importance to the development of the electric vehicle and energy storage industries, and various national incentive policies have been introduced. Chinese-made lithium titanate battery systems have accumulated several years of commercial application data in hybrid electric buses in Chongqing and Europe, the wind-solar-storage demonstration station in Zhangbei, and the Baoqing energy storage power station in Shenzhen.
Furthermore, my country's lithium battery industry chain is already well-established, with comprehensive battery material supply and equipment manufacturing capabilities. In addition, my country's lithium battery production capacity is on par with Japan and South Korea. This provides Chinese lithium battery manufacturers with inherent advantages for transitioning from traditional lithium battery production to lithium titanate battery production.
my country already has several experienced and capable companies in the production of lithium titanate materials, such as Sichuan Xingneng, Zhuhai Yinlong, and Huzhou Microvast. Leading companies in lithium titanate battery production include Huzhou Microvast, Zhuhai Yinlong, Shenzhen Boleda, and Tianjin Jiewei.
These companies have already established their own sales channels in the domestic and international electric vehicle and energy storage markets. It is particularly noteworthy that Shenzhen Boleda possesses a series of proprietary technologies and intellectual property rights, ranging from material production to battery manufacturing and system integration. Currently, it is one of the few manufacturers in China's lithium battery industry with independent intellectual property rights.
2. Bottlenecks in the fabrication of lithium titanate materials, batteries, and battery packs
Given that lithium titanate battery technology has many advantages that other lithium batteries cannot match, why has its application been so limited in China's energy industry and even the global energy sector to date? There are three main reasons:
① The production of lithium titanate materials is not complicated in principle. However, to be used as a negative electrode material in lithium-ion batteries, the material not only needs to have suitable specific surface area, particle size, density, and electrochemical performance, but it must also be compatible with large-scale lithium battery production processes. One of the reasons why lithium titanate materials cannot be produced normally on many traditional lithium battery production lines is that the material has a pH of 11 or 12 and is extremely hygroscopic.
② Lithium titanate battery manufacturing: In reality, directly using a conventional lithium-ion battery production line to produce lithium titanate batteries is not as simple as merely replacing graphite with lithium titanate. This is because lithium titanate has much higher humidity requirements than conventional lithium-ion battery production. To control humidity, some manufacturing processes need to be adjusted to meet the specific requirements of lithium titanate battery production. Furthermore, some production equipment also needs modification. Ideally, a compact, small-sized, fully enclosed automated production line should be redesigned specifically for lithium titanate battery products.
③ Lithium titanate battery packs differ from conventional lithium-ion batteries. Currently, after lithium titanate battery packs produced domestically and internationally have been in use for a period of time, trace amounts of gas are often observed within the individual cells of the pouch cells. These gases are different from those produced during the formation of fresh batteries. The former can be removed through battery manufacturing processes. However, the latter is generated during battery use, or rather, is difficult to avoid under current technological conditions.
The author believes that studying the chemical reaction mechanism of gas generation during cycling would be a promising research topic. Furthermore, one of the advantages of lithium titanate battery technology is its high power performance. Although the battery itself can withstand high current charging and discharging, thick individual cells are still unsuitable for high-power applications because excessive thickness makes it difficult to dissipate the heat generated by the high current. Therefore, for high-power lithium titanate batteries, a large but thin pouch cell structure remains a reasonable choice.
3. Future Development Direction of Lithium Titanate Technology
Finally, it is necessary to summarize the advantages and disadvantages of lithium titanate as a lithium battery anode. Advantages include: ultra-high safety, ultra-long lifespan, wide operating range at high and low temperatures, high power, low cost, and environmental friendliness. Disadvantages include: low energy density, high water absorption, demanding environmental requirements for battery manufacturing, need for corresponding updates to production processes, investment in necessary equipment and stricter humidity control for new processes, and the fact that the market for lithium titanate batteries is not yet fully developed.
Conclusion
In the current context of the Chinese government's strong advocacy for the development of new energy and related industries, promoting lithium titanate battery technology and its application in the electric vehicle and energy storage markets presents a golden opportunity for China's lithium titanate battery industry. This presents a unique opportunity for domestic companies such as Zhuhai Yinlong, Huzhou Microvast, Shenzhen Boleda, Sichuan Xingneng, and Shenzhen BTR, which possess independent intellectual property rights and established sales channels. Many people fail to realize that China's intellectual property advantages in lithium titanate technology are something that the so-called "mainstream chemistry," primarily based on lithium iron phosphate batteries, currently lacks.
Developing high-capacity, high-potential cathode materials to improve the energy density of lithium titanate batteries is a crucial step in catching up with Japan and South Korea. Of course, it is also essential to research the entire lithium-ion battery chemistry system, including topics such as high-potential electrolytes and antioxidant separators. The efforts of China's lithium battery industry in developing lithium titanate battery technology will yield substantial returns from the burgeoning markets of electric vehicles, energy storage, and industrial applications.
