Composite (bi-)metallic oxides with heterostructure and heteroatom-doped porous carbon as advanced potassium-ion battery anodes

In this work, a scalable two-step synthesis method was employed to develop transition metal oxide/carbon composites that exhibit excellent electrochemical performance as the anode of potassium-ion batteries. The functionalized metal-organic framework precursor was combined with molecular silicotungstic acid clusters (SiW9) during thermal conversion, and embedded into in-situ formed porous carbon matrix to form a multi-component CoWO4/WO3-C composite material with N-doping. Benefiting from unique compositional and structural features, the resulting composite exhibits an appealing potassium-ion storage performance, such as, large specific capacity of ca. 1500 mAh/g after 600 cycles and excellent rate capability, i. e., delivering reversible capacity over 200 mAh/g even at the high-rate of 2.0 A/g.