Lamellar network structure constructed by ZnSe/C nanorods for high-performance potassium storage

Abstract

The rapid development of promising potassium-ion batteries (PIBs) is still greatly hindered by typical constraints, including sluggish diffusion kinetics and structural degradation caused by severe volume vibration during the intercalation/deintercalation of K+. To eliminate such issues, herein we designed a novel lamellar network structure constructed by carbon-coated ZnSe/C nanorods (LN-ZnSe/C) as the anode of PIBs. The LN-ZnSe/C composite was synthesized via glucose-assisted freeze-drying and subsequent in-situ selenization of the zinc tartrate precursor. Kinetics analysis revealed that the nanosize and lamellar network structure of ZnSe/C enabled fast K-ion diffusion. Meanwhile, the carbon layer, as the binder and structure reinforcer of the ZnSe nanorods, provided a stable interconnected conductive network and enhanced the mechanical integrity of ZnSe for volume variation. Benefitting from these merits, LN-ZnSe/C revealed high reversible capacity (383 mA h g−1 at a current density of 200 mA g−1 after 100 cycles), superior rate capacity (230 mA h g−1 at 5 A g−1), and long cycling life (179 mA h g−1 after 1200 cycles at 1 A g−1). This work demonstrates a new promising development framework for fabricating network structures with a 3D charge-transport system to advance potassium-based energy storage devices.