N-doped carbon coating for stabilizing metal sulfides on carbon materials for high cycle life asymmetric supercapacitors

Manufacturing hybrid electrodes with the combination of electroactive materials and carbon carriers brings hope for high-performance supercapacitors, but the poor interfacial compatibility between hydrophobic carbon substrate surface and active materials is still the bottleneck to be solved. Here, we propose a superhydrophilic strategy to stabilize NiCo₂S₄ on inert carbon cloth (CC) using nitrogen-doped (N-doped) carbon layer as structure/interface coupling bridge, so as to prepare hybrid material (expressed as NiCo₂S₄/CC-CN) for supercapacitor. The N-doped carbon layer on CC leads to the formation of superhydrophilic surface/interface, which is conducive to the uniform growth of NiCo₂S₄ on CC and helps to effectively strong coupling interaction between CC and NiCo₂S₄. In addition, the asymmetric supercapacitor made of NiCo₂S₄/CC-CN as the positive electrode and as-prepared activated carbon cloth (PACC) as the negative electrode provides a high energy density of 0.11 mWh cm⁻² at a power density of 0.35 mW cm⁻². The interfacial engineering in this study holds the potential of creating high energy density electrodes for advanced energy storage.