Constructing bilayer heterogeneous organogel electrolytes of Lewis acidic/basic polymers to suppress self-discharge of supercapacitors

Abstract

Flexible supercapacitors with fast charging rate, long cyclic lifetime and high power density, but often suffer from their rapid self-discharge process, which remains a big challenge for their widely commercial application. Here, we for the first time report a bilayer heterogeneous organogel electrolyte (BHOE) consisting of a layer of Lewis acidic polymer (LAP) and a layer of Lewis basic polymer (LBP), to develop high-performance flexible supercapacitors with slow self-discharge process. The existing strong coordination interaction between the charged LAP (or LBP) and its counter anions (or cations) can effectively restrict the diffusion of ions accumulated on/in the electrodes into or throughout the bilayer electrolyte, which endowed the charged BHOE-based supercapacitor with slow self-discharge time (9.7 h) from its open-circuit voltage to the half, more than ten times longer than those (0.9 h) of devices based homogeneous LAP or LBP electrolytes. Furthermore, the BHOE-based supercapacitor possessed high capacitance retention up to 95 % after thousands of folding cycles, suggesting excellent mechanical flexibility. This study provides a novel strategy to build high-performance flexible supercapacitors with slow self-discharge, which is great meaningful for their practical application in the near future.