In situ decoration of nanosized metal oxide on highly conductive MXene nanosheets as efficient catalyst for Li-O2 battery

Combining nanomaterials with complementary properties in a well-designed structure is an effective tactic to exploit multifunctional, high-performance materials for the energy conversion and storage. Nonprecious metal catalysts, such as cobalt oxide, with superior activity and excellent stability to other catalysts are widely desired. Nevertheless, the performance of CoO nanoparticles as an electrode material were significantly limit for its inferior conductivity, dissolution, and high cohesion. Herein, we grow ultrafine cobalt monoxide to decorate the interlayer and surface of the Ti3C2Tx nanosheets via a hydrothermal method companied by calcination. The layered MXenes act as the underlying conductive substrate, which not only increase the electron transfer rate at the interface but also greatly improve the electrochemical properties of the nanosized CoO particles by restricting the aggregation of CoO. The resulting CoO/Ti3C2Tx nanomaterial is applied as oxygen electrode for lithium-oxygen battery and achieves more than 160 cycles and first cycle capacity of 16,220 mAh g−1 at 100 mA g−1. This work paves a promising avenue for constructing a bi-functional catalyst by coupling the active component of a transition metal oxide (TMO) with the MXene materials in lithium-oxygen battery.