Trimetallic MOF-Derived Cu0.39Zn0.14Co2.47O4–CuO Interwoven with Carbon Nanotubes on Copper Foam for Superior Lithium Storage with Boosted Kinetics

Transition metal oxides (TMOs), identified as a potential candidate for high-energy anode materials for state-of-the-art lithium-ion batteries (LIBs), suffer from the inherent defects of low electronic conductivity and dramatic volume variation, hindering their practical applications. It is still a great challenge to synthesize novel TMO anodes with satisfactory lithium storage performance. Herein, trimetallic Zn–Co–Cu-zeolitic imidazolate framework is designed with carbon nanotubes (CNTs) and copper foam (CF) serving as multifunctional bridges by postsynthetic metal-ion exchange and in situ solvothermal growth. After annealing, a novel trimetallic metal–organic framework (MOF)-derived polymetallic oxide, Cu0.39Zn0.14Co2.47O4–CuO@CNTs/CF hybrid, was successfully prepared. The introduction of conductive CNTs and a three-dimensional (3D) CF substrate effectively boosts the mechanical robustness and electronic conductivity of metal oxide composites, accelerates the lithium-ion diffusion, and reduces the impedance during the lithiation/delithiation process. When it is directly tested as a conductive-agent-free and binder-free electrode in LIBs, it presents distinguished long-cycling stability and high-rate capacity via the dominant mechanism of pseudocapacitive charge storage and the "electron-shared metal-Li+ double electric layer". The as-prepared Cu0.39Zn0.14Co2.47O4–CuO@CNTs/CF electrode delivers a high specific capacity of 1649 mAh g–1 at 0.2 A g–1 together with 1282 mAh g–1 at 5 A g–1 over 1000 cycles. The novel 3D self-supported MOF-derived polymetallic oxide synthetic strategy proposed in this work sheds light on creation of potential anode materials for next-generation LIBs.