Pre-intercalation chemistry of electrode materials in aqueous energy storage systems

Pre-intercalation, an interfacial engineering method, is found to be an effective way to stabilize the structure, enhance the ionic conductivity and shield the electrostatic interaction between carriers and electrode materials so as to facilitate the diffusion kinetics in energy storage system. As an alternative for lithium-ion batteries using organic solution as electrolyte, aqueous energy storage systems (AESSs) are becoming potential candidates for grid scale energy storage. However, the inferior conductivity, structural instability of the host materials and the strong electrostatic interaction between charge carriers and lattice lead to sluggish diffusion kinetics, hindering the exploitation of high-performance electrodes. To inspire innovative research directions and build high-performance hosts for AESSs, this review focuses on the functions, methods and applications of pre-intercalation engineering in electrode materials with different structures for AESSs and analyze the challenges that pre-intercalation faces. Besides, the prospect of next-generation pre-intercalated electrode materials is brought up.