Enabling two-electron redox chemistry of P-type organic cathode for high-capacity aluminium-ion batteries

Abstract

P-type organic cathodes (p-OCs) hold great promise in aluminium-ion batteries (AIBs), however current p-OCs exhibit apparent one or less than one electron redox processes and low capacities. Herein, we report a compromised electron-donating substitution strategy to excite 1-aminopyrene (ANP), a pyrene (Pyr) derivative, to undergo two-electron transfer, achieving a high specific capacity of 212 mA g−1 and excellent rate/long cycling performances (e.g., 106 mAh g−1 at 10 A g−1 for 12,000 cycles), superior over reported organic AIB cathodes. The electronic and steric effects of substitutes in a variety of Pyr derivatives on their functionality have been revealed. The electron-donating effect of the amino group plays two different roles, one in favoring the electron removal of neutral Pyr derivatives, another in reducing the positive charge density of oxidized radical cations. Collectively, ANP with the compromised electron-donating effect exhibits the highest binding energy with AlCl4- and reasonable voltage within the electrolyte working threshold, enabling the unprecedented two-electron transfer.