2D titanium carbide and transition metal oxides hybrid electrodes for Li-ion storage

The combination of nanomaterials with complementary properties in a well-designed architecture is an attractive strategy to develop multi-functional, high-performance materials for applications in energy conversion and storage, catalysis, electronic devices, and more. Herein, we propose three different methods: alternating filtration, spray coating, and in-situ wet chemistry synthesis, to achieve the hybridization of two-dimensional (2D) Ti₃C₂T_x MXene and transition metal oxides (TMOs), such as Co₃O₄ and NiCo₂O₄. The resulting flexible free-standing hybrid films were free of binders, conductive additives, or current collectors. When used directly as anodes for Li-ion batteries, these hybrid films successfully combined the metallic conductivity of Ti₃C₂T_x and high capacity of TMOs, showing excellent electrochemical performance for Li-ion storage. High reversible capacities over 1200 mA h g⁻¹ were achieved by the MXene/TMO hybrid film electrodes fabricated by all three methods. All films also exhibited impressive long cycling stabilities and excellent rate performances. In particular, the spray-coated Ti₃C₂T_x/NiCo₂O₄ hybrid film electrode achieved high reversible capacities of 1330, and 650 and 350 mA h g⁻¹ at 0.1, 5 and 10 C, respectively, along with no capacity decay over hundreds of cycles. This work demonstrates that the hybridization of MXenes, a large family of 2D transition metal carbides/nitrides, and TMOs has a significant potential for energy storage, and is promising for expansion into other applications.