Enhancing the lithium-ion storage capability of Cu₂ZnSnS₄ anodes via a nitrogen-doped conductive support

Achieving lithium-ion batteries with both excellent electrochemical performance and cycling stability is a top priority for their real-world applications. This work reports high-performance and stable Cu₂ZnSnS₄ (CZTS) anode materials encapsulated by nitrogen-doped carbon (CZTS@N-C) for advanced lithium-ion battery application. Ex-situ X-ray photoelectron spectroscopy and transmission electron microscopy revealed that the nitrogen-doped carbon network features a more conducive solid-electrolyte interphase that enables lower charge-transfer resistance and fast Li⁺ diffusion kinetics with negligible initial irreversible capacity loss. As a result, the CZTS@N-C electrode delivers a significantly enhanced capacity of 710 mAh g⁻¹ with 73% capacity retention after 220 cycles at a current rate of 0.5 mA g⁻¹ and superior rate performance compared to that of unmodified CZTS. Additionally, the study sheds light on the fast lithiation dynamics chemistry of CZTS@N-C through kinetics analysis, explored by in-situ Raman, ex-situ X-ray absorption, and in-situ electrochemical impedance. This study provides a new approach for fabricating high-performance, durable conductive polymer-encapsulated low-cost transition-metal-sulfide anode materials.