高比能锂离子电池层状富锂正极材料改性策略研究进展

层状富锂材料具有超过250 mAh·g-1的高可逆比容量,被认为是下一代高比能锂离子电池最具商业化前景的正极材料之一。然而,层状富锂材料在实际应用之前仍需解决诸多挑战,如高电压氧释放、层状到岩盐相的结构变化、过渡金属离子迁移等结构劣化,并由此带来了较低的初始库伦效率、电压/容量的衰减以及循环寿命的不足。针对以上问题,进行层状富锂材料改性无疑是一种行之有效的方法。本综述全面介绍了层状富锂材料的结构、组分以及电化学性能,在此基础上对材料改性策略进行了系统阐述,详细介绍了体相掺杂、表面包覆、缺陷设计、离子交换和微结构调控等一系列改性策略的现状以及发展趋势,最终提出了高容量和长循环层状富锂材料和高比能锂离子电池的设计思路。

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.

Progress on multiphase layered transition metal oxide cathodes of sodium ion batteries

As one of the most promising secondary batteries in large-scale energy storage,sodium ion batteries(SIBs) have attracted wide attention due to the abundant raw materials and low cost.Layered transition metal oxides are one kind of popular cathode material candidates because of its easy synthesis and large theoretical specific capacity.Yet,the most common P2 and O3 phases show distinct structural characteristics respectively.O3 phase can serve as a sodium reservoir,but it usually suffers from serious phase transition and sluggish kinetics.For the P2 phase,it allows the fast sodium ion migration in the bulk and the structure can maintain stable,but it is lack of sodium,showing a great negative effect on Coulombic efficiency in full cell.Thus,single phase structure almost cannot achieve satisfied comprehensive sodium storage performances.Under these circumstances,exploiting novel multiphase cathodes showing synergetic effect may give solution to these problems.In this review,we summarize the recent development of multiphase layered transition metal oxide cathodes of SIBs,analyze the mechanism and prospect the future potential research directions.