Solid-state Li-air batteries:Fundamentals,challenges,and strategies

The landmark Net Zero Emissions by 2050 Scenario requires the revolution of today's energy system for realizing nonenergy-related global economy.Advanced batteries with high energy density and safety are expected to realize the shift of end-use sectors toward renewable and clean sources of electricity.Present Li-ion technologies have dominated the modern energy market but face with looming challenges of limited theoretical specific capacity and high cost.Li-air(O2)battery,characterized by energy-rich redox chemistry of Li stripping/plating and oxygen conversion,emerges as a promising“beyond Li-ion”strategy.In view of the superior stability and inherent safety,a solid-state Li-air battery is regarded as a more practical choice compared to the liquid-state counterpart.However,there remain many challenges that retard the development of solid-state Li-air batteries.In this review,we provide an in-depth understanding of fundamental science from both thermodynamics and kinetics of solid-state Li-air batteries and give a comprehensive assessment of the main challenges.The discussion of effective strategies along with authoritative demonstrations for achieving highperformance solid-state Li-air batteries is presented,including the improvement of cathode kinetics and durability,solid electrolyte design,Li anode optimization and protection,as well as interfacial engineering.