Poor cycling stability,as a long-standing issue,has greatly hindered the commercial application of Li-rich layered oxide cathodes in high-energy-density Li-ion batteries.NiO-type rock-salt phase is commonly considered...Poor cycling stability,as a long-standing issue,has greatly hindered the commercial application of Li-rich layered oxide cathodes in high-energy-density Li-ion batteries.NiO-type rock-salt phase is commonly considered electrochemically inert but stable.Herein,an ultrathin(LixTM1-x)O rock-salt shell was in situ constructed at the particle surface during the synthesis of Li-rich layered oxide cathodes through a unique soft chemical quenching method.Comprehensive structural/chemical analysis reveals that,it not only inherits the chemical stability of traditional NiO-type rock-salt phase,but also facilitates Li^+diffusion due to the co-occupancy of Li^+and TM cations.Such a bifunctional shell could efficiently prevent TM dissolution and oxygen evolution during the long-term cycling,eventually leading to the enhanced cycling stability for Li-rich layered oxides(92.7%of capacity retention after 200 cycles at 0.5 C).It provides new guidance to design and synthesize new Li-rich layered oxides with the excellent cycling stability through utilizing some electrochemically-inert phases.展开更多
基金Supported by National Key R&D Program of China(2016YFB0700600)Soft Science Research Project of Guangdong Province(No.2017B030301013)Shenzhen Science and Technology Research Grant(ZDSYS201707281026184)。
文摘Poor cycling stability,as a long-standing issue,has greatly hindered the commercial application of Li-rich layered oxide cathodes in high-energy-density Li-ion batteries.NiO-type rock-salt phase is commonly considered electrochemically inert but stable.Herein,an ultrathin(LixTM1-x)O rock-salt shell was in situ constructed at the particle surface during the synthesis of Li-rich layered oxide cathodes through a unique soft chemical quenching method.Comprehensive structural/chemical analysis reveals that,it not only inherits the chemical stability of traditional NiO-type rock-salt phase,but also facilitates Li^+diffusion due to the co-occupancy of Li^+and TM cations.Such a bifunctional shell could efficiently prevent TM dissolution and oxygen evolution during the long-term cycling,eventually leading to the enhanced cycling stability for Li-rich layered oxides(92.7%of capacity retention after 200 cycles at 0.5 C).It provides new guidance to design and synthesize new Li-rich layered oxides with the excellent cycling stability through utilizing some electrochemically-inert phases.
