Double shell Li rich layered oxide hollow microspheres with sandwich like carbon@spinel@layered@spinel@carbon shells as high rate lithium ion battery cathode
Abstract Li rich layered oxides (LRLO) with high specific capacity over 250 mA h g 1 are attractive cathode material candidates for the next generation high performance lithium ion batteries. However, LRLO always suffers from low initial Coulombic efficiency, poor cycling and rate properties. Herein, unique double shell LRLO hollow microspheres with sandwich like carbon@spinel@layered@spinel@carbon shells (LRLO 500@S@C) were successfully synthesized via a facile template free method, followed by carbothermal reduction treatment. The fabricated LRLO 500@S@C cathode delivers a high initial charge capacity of 312.5 mA h g 1 with a large initial Coulombic efficiency of 89.7% After cycling 200 times, large and stable discharge capacities of 228.3 mA h g 1 and 196.1 mA h g 1 can be obtained at 1.0 C and 5.0 C, respectively. Moreover, coin type full cell with LRLO 500@S@C as cathode and Li4Ti5O12 as anode delivers outstanding lithium storage properties. The impressive electrochemical performances of LRLO 500@S@C cathode material can be attributed to its multiscale coordinated design based on hierarchical double shell hollow construction, the special layered@spinel@carbon heterostructured shells and the introduced oxygen vacancies, which benefit to shorten Li ion diffusion paths, strengthen structural stability and reduce side reactions.
Nano Energy