Solid-state batteries are widely recognized as the next generation of power batteries, and they may replace lithium-ion batteries with liquid electrolytes. Currently, companies including CATL, BYD, and Guoxuan High-Tech claim to have in-depth research in this field, but the specifics remain unknown.
So, what are the advantages and disadvantages of solid-state batteries compared to the mainstream lithium-ion batteries currently on the market?
Advantage 1: Good safety.
Liquid electrolytes are flammable and explosive, and the growth of lithium dendrites during charging can easily puncture the separator, causing a short circuit and posing a safety hazard. Solid-state electrolytes, on the other hand, can suppress lithium dendrites, are not easily flammable or explosive, do not leak electrolyte, and do not undergo side reactions at high temperatures. In other words, they will not puncture the separator and cause a short circuit under high current, will not undergo side reactions at high temperatures, and will not burn due to gas generation. Therefore, safety is considered one of the most fundamental driving forces for the development of solid-state batteries.
Advantage 2: High energy density
Liquid electrolyte batteries can achieve a maximum energy density of 300 Wh/kg, but exceeding 500 Wh/kg is considered impossible. With all-solid-state electrolytes, batteries can eliminate the need for lithium-intercalated graphite anodes, instead using metallic lithium directly. This significantly reduces the amount of anode material used, resulting in a substantial increase in overall battery energy density. Solid-state battery development can currently provide energy densities of 300-400 Wh/kg.
Advantage 3: Strong cycle performance.
Solid electrolytes solve the problems of solid electrolyte interface film and lithium dendrite formation during the charging and discharging process of liquid electrolytes, greatly improving the cycle life and service life of lithium batteries. Under ideal conditions, the cycle performance is excellent and can reach about 45,000 cycles.
Advantage 4: Expanded scope of application.
Solid-state electrolytes endow solid-state lithium batteries with features such as compact structure, adjustable scale, and high design flexibility, enabling them to be used in driving microelectronic devices as well as in power and energy storage applications. Furthermore, solid-state batteries also have a wider operating temperature range, currently generally maintaining a temperature range of -25℃ to 60℃.
While possessing advantages, solid-state batteries also have extremely significant drawbacks. These drawbacks are precisely the problems that need to be addressed in the research and development of solid-state batteries.
Disadvantage 1: Excessive interface impedance.
The interface between the solid electrolyte and the electrode material is in a solid-solid state, resulting in weak effective contact between the electrode and the electrolyte, and low ion transport kinetics in the solid material.
Disadvantage 2: The cost is relatively high.
It is understood that the cost of liquid lithium batteries is approximately $120-200 per kWh. If solid-state batteries capable of powering smartphones are manufactured using existing technology, the cost would be close to $10,000, while solid-state batteries capable of powering automobiles would cost an astonishing $50 million or more.
The generally low conductivity of solid electrolytes leads to their generally low rate performance, high internal resistance, slow charging speed, and generally high cost. As a result, solid batteries do not have much of an advantage in competing with ordinary lithium-ion batteries in the traditional market.
Therefore, leveraging the inherent high safety, high-temperature stability, and potential flexibility of solid-state batteries to compete with traditional lithium-ion batteries in a differentiated market may be a promising direction for market breakthroughs in the near future.
