Sacrificial templating synthesis of rod-like LiNixMn2−xO4 spinels and their improved cycling performance

Abstract

Nanofabrication of crystalline materials has been well recognised as one of the most efficient pathways to improve the electrochemical performance of an electrode on the principle of lithium-ion insertion/extraction depth. Herein, it is reported that freshly prepared β-MnO2 nanorods have been successfully used as sacrificial templates to synthesise the rod-like spinels of pristine LiMn2O4 with high purity and good crystallinity. Under the optimum sintering temperature of 750°C for 10 h, the presence of doping reactant Ni(CH3COO)2·4H2O can greatly weaken the templating effectiveness of β-MnO2 nanorods, effectively resulting in LiNixMn2−xO4 (x=0.025, 0.05 and 0.1) samples with a relatively short aspect ratio. Galvanostatic charge–discharge tests showed that the undoped rods could acquire an initial discharge capacity of 125.9 mAh/g at 1 C and the corresponding capacity retention of 75.3% after 100 cycles. Interestingly, with the increase of element-doped amount, the resulting LiNixMn2−xO4 displayed a gradually improved cyclability at the charge–discharge rate of 1 C at room temperature.