First, lithium-ion power batteries are expected to achieve the target of 300 Wh/kg by 2020. Currently, domestic and foreign technology research and development are basically at the same level, but safety research needs to be strengthened. The core of this type of battery is safety.
Secondly, for new energy passenger vehicles, especially sedans, the requirement for volumetric energy density may be more important than gravimetric energy density. While some batteries have a specific energy density of 400 Wh/kg, their volumetric energy density is only 400 Wh/L, which is not ideal for sedans. Generally, lithium-ion batteries can achieve a gravimetric energy density of 300 Wh/kg and a volumetric energy density of 600 Wh/L. Lithium-air batteries combine the challenges of zinc-air batteries, hydrogen fuel cell batteries, and lithium-ion batteries. In comparison, hydrogen fuel cell batteries have a greater competitive advantage.
Third, the research and industrialization of solid-state batteries continues to heat up, but due to two major constraints—solid-solid interface stability and the rechargeability of lithium metal anodes—true all-solid-state lithium-ion battery technology is not yet mature. However, breakthroughs have been made in lithium-ion batteries using inorganic sulfides as solid electrolytes. Overall, the development path of solid-state batteries suggests that electrolytes may evolve from liquid, semi-solid, and solid-liquid hybrids to solid, and finally to all-solid-state. As for the anode, it will evolve from graphite anodes to silicon-carbon anodes and then to alloyed anodes. We are currently transitioning from graphite anodes to silicon-carbon anodes, and ultimately, lithium metal anodes may be used, but there are still technological uncertainties.
Fourth, my country made some breakthroughs in high-capacity lithium-rich cathode materials in 2017. Innovative lithium-ion batteries based on high-capacity lithium-rich cathodes and high-capacity silicon-carbon anodes are more feasible than lithium-sulfur and lithium-air batteries.
