In situ self-transformation strategy toward zinc selenide electrode for lithium-ion capacitors

Abstract

Conversion/alloying mechanism anode materials, featuring its higher theoretical capacity, have been deemed to one of the most potential candidates in the context of lithium ion capacitors (LICs). Nevertheless, the Li+ diffusion sluggish kinetics and severe volume variations during repeatedly lithiation/delithiation process further impede their application. Herein, an in situ self-transformation strategy is proposed to unlock the cyclic stability of electrode material. Multiple characterization techniques are adopted to unfold the electrode storage mechanism, the evolution of crystal structure, as well as the kinetics after reconstruction. The hexagonal wurtzite (WZ) in rGO-coupled ZnSe would be transformed spontaneously to cubic zinc-blende (ZB) phases upon the first electrochemical cycling with Li+. Consequently, the WZ-ZnSe@rGO electrode delivers dramatically cycling stability (451 mAh g−1 after 220 cycles at 0.1 A g−1). Additionally, we also prepare cubic m-ZB-ZnSe@rGO through physical mixing method, exhibiting high Li-storage capacity (468 mAh g−1 at 0.1 A g−1). This work suggests that in situ self-transformation strategy is feasible for creating high-performance electrode materials.