Crystal, interfacial and morphological control of electrode materials for nonaqueous potassium-ion batteries

Abstract

In the existing battery system, non-aqueous potassium-ion batteries (PIBs) have attracted considerable interest and exhibited a broad application prospect in the prospective large-scale energy storage due to the abundant and cost-effective resources, fast K-ion conductivity in electrolyte and low standard reduction potential of K+/K. After tremendous efforts for ideal electrode materials and full-cells assembly technologies, the comprehensive performance of PIBs including K-ion diffusion kinetics, K storage capacity and reversibility, has made great progress. This review features our current understanding and the development status of PIBs from the perspective of crystal, interfacial and morphological control on electrode materials for nonaqueous PIBs, including i) the correlation between the lattice structure of electrode material (interlayer spacing, lattice parameter, etc.) and the K+ storage/transfer, ii) K+ transfer/reaction kinetics in two-phase interface and the relationship between phase interface and structural stability and iii) the development status and law of the relationship between morphology and volume strain or K+/electron transfer rate. The summary and perspectives aim to address the crucial issues and explore high-performance PIBs, which may provide a guidance for other energy storage devices. Future research hotspots and other key issues that need to be addressed are outlined.