Fabrication of multi-layer CoSnO3@carbon-caged NiCo2O4 nanobox for enhanced lithium storage performance

Abstract Mixed transition metal oxides (MTMOs) are deemed as promising anode materials for lithium-ion batteries (LIBs) because of the high theoretical capacity and low cost. However, the low electrical conductivity, agglomeration effects, and huge volume variation during discharging/charging still seriously restrict the actual applications of MTMOs as anode materials. Herein, a novel core-shell structure of CoSnO3@carbon-caged NiCo2O4 nanobox (CNC) is rationally designed. It starts from the preparation of CoSnO3@ZIF-67 core-shell nanocubes, followed by chemical etching/anion exchange, dopamine coating and carbonization at high temperature in sequence. It is shown that the CNC achieves high activities from the applied MTMOs components, excellent relief of volume variation from the unique double hollow structure, improved conductivity and inhabited aggregations from the uniform-coated outmost carbon shell, and effective ion/electron transfer rates from the synergetic effects. As a result, the CNC exhibits a discharge capacity of 1548 mA h g-1 at the first cycle and retention capacity of 992 mA h g-1 after 100 cycles at 0.1 A g-1. In addition, it exhibits a high reversible capacity of about 670 mA h g-1 after 500 cycles at a current density of 1 A g-1. The improved Li+ storage performances of CNC demonstrates that such rational design of double hollow structure could be a novel strategy to apply MTMOs as anode materials of LIBs.