Controlled formation of core-shell structures with uniform AlPO4 nanoshells.

Uniform AlPO4 nanoshells are successfully achieved on different core materials by controlling their formation kinetics in solution. The application of this coating protocol to LiCoO2 shows an obvious improvement in its battery performance.

Optimizing LiFePO4@C core-shell structures via the 3-aminophenol-formaldehyde polymerization for improved battery performance.

Polyanion-type cathode materials are well-known for their low electronic conductivity; accordingly, the addition of conductive carbon in the cathode materials becomes an indispensable step for their application in lithium ion batteries. To maximize the contribution of carbon, a core-shell structure with a full coverage of carbon should be favorable due to an improved electronic contact between different particles. Here, we report the formation of a uniform carbon nanoshell on a typical cathode material, LiFePO4, with the shell thickness precisely defined via the 3-aminophenol-formaldehyde polymerization process. In addition to the higher discharge capacity and the improved rate capability as expected from the carbon nanoshell, we identified that the core-shell configuration could lead to a much safer cathode material as revealed by the obviously reduced iron dissolution, much less heat released during the cycling, and better cyclability at high temperature.