Colloidal Supercapattery: Redox Ions in Electrode and Electrolyte

Abstract

Redox chemistry is the cornerstone of various electrochemical energy conversion and storage systems, associated with ion diffusion process. To actualize both high energy and power density in energy storage devices, both multiple electron transfer reaction and fast ion diffusion occurred in one electrode material are prerequisite. The existence forms of redox ions can lead to different electrochemical thermodynamic and kinetic properties. Here, we introduce novel colloid system, which includes multiple varying ion forms, multi-interaction and abundant redox active sites. Unlike redox cations in solution and crystal materials, colloid system has specific reactivity-structure relationship. In the colloidal ionic electrode, the occurrence of multiple-electron redox reactions and fast ion diffusion leaded to ultrahigh specific capacitance and fast charge rate. The colloidal ionic supercapattery coupled with redox electrolyte provides a new potential technique for the comprehensive use of redox ions including cations and anions in electrode and electrolyte and a guiding design for the development of next-generation high performance energy storage devices.

Keywords: colloid; electroactive ions; energy storage; redox chemistry; redox electrolyte.