Integrate electrical conductivity and Li+ ion mobility into hierarchical heterostructure Ti3C2@CoO/ZnO composites toward high-performance lithium ion storage

Abstract

The structural instability and low electrical conductivity of CoO and ZnO cause their rapid capacity fading when it is used for lithium ion storage, which limits their applications. In response, a hierarchical heterostructure was formed by anchoring CoO/ZnO nanodots onto the surface of Ti3C2 to effectively address the above issue. Ti3C2 has an excellent electrochemical performance which can effectively enhance the electrical conductivity of CoO/ZnO and facilitate lithium ion mobility, and CoO/ZnO nanodots that are uniformly anchored on the Ti3C2 surface can effectively inhibit the aggregation of CoO/ZnO nanodots during cycling. As an anode electrode for lithium-ion batteries, the Ti3C2@CoO/ZnO electrode exhibits a high reversible capacity (1069 mA h g−1 at 0.2 A g−1 for over 120 cycles), excellent cycleability (1052 mA h g−1 at 0.5 A g−1 for over 200 cycles, and 627 mA h g−1 at 1 A g−1 for over 300 cycles) and exceptional rate capacity (498 mA h g−1 at 3 A g−1, and holds 794.3 mA h g−1 after 110 cycles when the current is controlled at 0.1 A g−1 again). This work paves the way for the structural modification of other types of metal oxides (sulfides) to enhance electrochemical performance.