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

A novel bilayer heterogeneous organogel electrolyte of Lewis acidic/basic polymers is developed to suppress rapid self-discharge rate of supercapacitors. The effect of coordination interaction between Lewis acidic/basic polymers and their conjugated base/acid on the self-discharge rate of supercapacitor is revealed. [Display omitted] •A novel bilayer heterogeneous organogel electrolyte (BHOE) of Lewis acidic/basic polymers is constructed.•The fabricated BHOE-based supercapacitor shows high capacitance and slow self-discharge rate.•The suppressing mechanism of the BHOE on self-discharge of supercapacitors is revealed.•The developed supercapacitor exhibits excellent mechanical flexibility and stability. 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.