摘要
The Ni-richLiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered cathodes endow Li-ion batteries(LIBs)with high energy density.However,they usually suffer from limited ion-diffusion and structural instability during cycling.Although doping strategy can effectively alleviate these issues,the coupling effects of multi-element doping and the corresponding performance enhancement mechanism have been yet unclear.Here,we report a Zr/Ti dual-doped NCM811 cathode material(ZT-NCM811),in which Zr-ion is doped into both transition metal(TM)layers and lithium layers and Ti-ion is only distributed in TM layers.The dual-doping can effectively enhance crystal structure stability via inhibiting the lattice collapse along c-axis and decreasing the Li/Ni disorder.Meantime,the lattice oxygen escape is also greatly reduced due to the presence of stronger Zr-O and Ti-O bonds,further mitigating the crystal surface parasitic reactions with electrolyte.The resultant ZT-NCM811 exhibits high specific capacity of 124 m Ah/g at even 10 C,much higher than undoped and single-doped NCM811,and a retention of 98.8%at 1 C after 100 cycles.The assembled ZT-NCM811/graphite full cell also delivers superior battery performances and durability.
基金
supported by the National Natural Science Foundation of China(Nos.21975074,91834301)
the Innovation Program of Shanghai Municipal Education Commission
the Fundamental Research Funds for the Central Universities。
