Designed formation of nitrogen-doped caramel sheathed bilateral hybrid oxides nanoarrays as ultra-stable anode for high-areal-capacity lithium-ion batteries

Nanoarrays have aroused great concern in boosting the cyclic stability of lithium-ion batteries because of their prominent superiorities in shortening diffusion path of Li⁺ ions, and resolving disadvantages of poor anchor ability of active materials. Herein, bilateral nanoarrays self-supporting electrode composed of Coca-Cola-based N-doped caramel sheathed NiCo₂O₄/Co₃O₄/Al₂O₃ in-situ anchored on Ni foam substrate was synthesized via microwave-assisted method. The morphologies of the inner and outer sides of Ni foam substrate are different. The in-situ formation of bilateral nanoarrays not only causes dissolution of interlayer to ingeniously form NiCo₂O₄, but also reinforces adhesion. Coca-Cola-based unique N-doped micro-mesoporous caramel is used for the first time to boost electrochemical performance. Specifically, the carbon/binder free bilateral nanoarrays electrode composed of Coca-Cola-based caramel sheathed NiCo₂O₄/Co₃O₄/Al₂O₃ possess a high reversible capacity (1.28 mA h cm⁻² at 0.5 mA cm⁻² for 200 cycles), exhibit ultra-stable and high rate cyclic stability (0.27 mA h cm⁻² at 4 mA cm⁻² over 2500 cycles, and 0.25 mA h cm⁻² at a high rate of 6 mA cm⁻² over 1500 cycles). This work proposes a rational strategy to enhance electrochemical performance for hybrid oxides self-supporting electrode.