The development of next-generation layered oxide cathodes for high-energy-density electrical vehicle Li-ion batteries(LIBs)is an urgent topic.The existing method is achieved by continuously increasing the Ni contents ...The development of next-generation layered oxide cathodes for high-energy-density electrical vehicle Li-ion batteries(LIBs)is an urgent topic.The existing method is achieved by continuously increasing the Ni contents of Ni-based layered oxides,but it has been limited to LiNiO_(2).To break this limit and attain increased energy densities,a promising strategy,which involves the introduction of excess Li ions into transition metal(TM)layers to form Li-excess compounds Li_(2)MO_(3)(M is a TM cation),has attracted enormous interest recently.However,another strategy,which has been neglected in recent years,involves the insertion of an extra layer of Li ions between the TM and original Li layers to form Li_(2)MO_(2).In this study,typical reversible Li_(2)NiO_(3) and 1T-Li_(2)NiO_(2) were selected as two representative cathodes to break the limit of LiNiO_(2),thereby availing comprehensive comparison with LiNiO_(2) regarding their overall properties as cathodes from a theoretical perspective.Interestingly,dissimilar to the Ni^(3+)/Ni^(4+)monoelectron cationic redox associated with LiNiO_(2),a polaronic anionic redox reaction occurs in Li_(2)NiO_(3),while a reversible Ni^(2+)/Ni^(4+)double-electron redox reaction accompanied by insulator-metal transition occurs in Li_(2)NiO_(2).Owing to this double-electron cationic activity,Li_(2)NiO_(2) exhibits absolute advantages over the other two materials(LiNiO_(2) and Li_(2)NiO_(3))as cathodes for LIBs in terms of the capacity,energy density,electronic conductivity,and thermal stability,thus rendering it the most promising candidate for next-generation layered oxide cathodes with high energy densities to break the limit of LiNiO_(2).展开更多
基金financially supported by the starting fund of Peking University,Shenzhen Graduate School and Fujian Science&Technology Innovation Laboratory for Energy Devices of China(21C-LAB)。
文摘The development of next-generation layered oxide cathodes for high-energy-density electrical vehicle Li-ion batteries(LIBs)is an urgent topic.The existing method is achieved by continuously increasing the Ni contents of Ni-based layered oxides,but it has been limited to LiNiO_(2).To break this limit and attain increased energy densities,a promising strategy,which involves the introduction of excess Li ions into transition metal(TM)layers to form Li-excess compounds Li_(2)MO_(3)(M is a TM cation),has attracted enormous interest recently.However,another strategy,which has been neglected in recent years,involves the insertion of an extra layer of Li ions between the TM and original Li layers to form Li_(2)MO_(2).In this study,typical reversible Li_(2)NiO_(3) and 1T-Li_(2)NiO_(2) were selected as two representative cathodes to break the limit of LiNiO_(2),thereby availing comprehensive comparison with LiNiO_(2) regarding their overall properties as cathodes from a theoretical perspective.Interestingly,dissimilar to the Ni^(3+)/Ni^(4+)monoelectron cationic redox associated with LiNiO_(2),a polaronic anionic redox reaction occurs in Li_(2)NiO_(3),while a reversible Ni^(2+)/Ni^(4+)double-electron redox reaction accompanied by insulator-metal transition occurs in Li_(2)NiO_(2).Owing to this double-electron cationic activity,Li_(2)NiO_(2) exhibits absolute advantages over the other two materials(LiNiO_(2) and Li_(2)NiO_(3))as cathodes for LIBs in terms of the capacity,energy density,electronic conductivity,and thermal stability,thus rendering it the most promising candidate for next-generation layered oxide cathodes with high energy densities to break the limit of LiNiO_(2).
