Construction of sugar gourd-like yolk-shell Ni–Mo–Co–S nanocage arrays for high-performance alkaline battery

Abstract

Mixed transition metal sulfides (TMSs) with hollow and complex hollow structures have attracted intensive attentions as high-performance cathode materials for rechargeable alkaline batteries. However, these powder-based electrode materials should be further mixed with insulative polymer binders and suffered from complicate electrode fabrication process. Herein, for the first time, we demonstrate the delicate design and synthesis of the sugar gourd-like multi-component yolk-shell Ni–Mo–Co–S nanocage arrays (NCAs) on Ni foam (NF) through a facile metal-organic framework (MOF)-engaged strategy. The synthetic process includes the growth of Co-based zeolitic imidazolate framework (ZIF-67) polyhedra onto the NiMoO4·xH2O nanorod arrays (NRAs) at room temperature and followed by a sufficient sulfidation reaction. Benefiting from the intriguing structural and compositional advantages, the yolk-shell Ni–Mo–Co–S NCAs/NF binder-free electrode exhibits an extremely high areal capacity of 1.96 mAh cm−2 at a current density of 5 mA cm−2 and excellent cycling stability. The electrode kinetics analysis confirms the diffusion-controlled battery-type behavior of the yolk-shell Ni–Mo–Co–S NCAs/NF electrode. The corresponding full cell delivers an high energy density of 92.6 Wh kg−1 at the power density of 1029.1 W kg−1 with the yolk-shell Ni–Mo–Co–S NCAs/NF as cathode electrode and Bi2O3 as anode electrode, indicating the potential for real applications. This work would make contribution to the realization of directly growing multi-component hollow and complex hollow structures on conductive substrate for high-performance electrochemical energy storage.