Formation of highly porous CuCo2O4 nanosheet assemblies for high-rate and long-term lithium storage

Mixed transition metal oxides with high theoretical capacity show great potential to replace carbonaceous anode materials in lithium-ion batteries. However, they usually undergo large volume change during lithiation/delithiation, leading to poor rate and cycling performance. In this work, unique microsized assemblies constructed from porous CuCo2O4 nanosheets are synthesized by a facile method. Benefiting from the desired structural and compositional features, the as-synthesized CuCo2O4 nanosheet assemblies manifest excellent lithium storage performance in terms of high rate capability and long-term cycling stability. Specifically, the CuCo2O4 nanosheet assemblies can deliver a high specific capacity of 1104 mA h g−1 at 2 A g−1 after 600 cycles. Even at a high rate of 5 A g−1, a high specific capacity of 656 mA h g−1 can still be achieved.