Journal:Chem. Electro. Chem
Abstract:To mitigate the gradual phase transition and improve the structural stability of Li-rich layered cathode materials, an antisite defect nanolayer (transition-metal ions replacing Li+ in a Li slab) with a thickness of approximately 2 nm was induced on the surface of Li1.16(Ni0.25Mn0.75)0.84O2 by doping with boracic polyanions. It is found that the 2 and 3 mol % BO 3 -doped 3 samples show excellent cycling stability with capacity retentions of 91.2 and 93.7 %, respectively, after 300 cycles at 0.5 C. More importantly, the BO 3 doping restrains the decay of discharge 3 voltage upon cycling and has the prospect to overcome the fatal drawback of Li-rich layered oxides. The results demonstrate that the BO 3 doping contributes to the generation of an 3 antisite defect nanolayer on the surface, which hinders the formation of Li-ion vacancies and the continued migration of more transition-metal ions to the Li slab in a deep charging state. The antisite defect nanolayer clearly improves surface structural stability and inhibits the appearance of the amor- phous domain in the bulk, which are favorable to maintain the facile lithium-diffusion pathways during cycling and improve the capacity retention and rate capability.
Indexed by:Journal paper
Translation or Not:no
Date of Publication:2017-01-01