A pressure-alignable liquid crystalline gel enables efficient energy conversion in self-charging piezo-supercapacitor

An isotropic gel piezo-electrolyte generates piezoelectric potential when subjected to a compressive force but exhibits a relatively constant ionic conductivity under different pressures. Here, we present a pressure-alignable liquid crystalline gel (LCG) piezo-electrolyte to simultaneously enhance ionic conductivity along with piezoelectric generation for an efficient piezo-supercapacitor. The LCG piezo-electrolyte is obtained via converting 4-(1-ethyldecyl) benzenesulfonic acid (EDBSA) lyotropic liquid crystal filled with piezoelectric barium titanate particles into polyacrylamide hydrogel. An external pressure induces macroscopic alignment of lamellar EDBSA self-assembly and results in an increase in the ionic conductivity, from 48.5 mS cm −1 to 58.5 mS cm −1 . By virtue of the simultaneous conductivity promotion and piezoelectric generation, the piezo-supercapacitor constructed from the LCG piezo-electrolyte and carbon cloth-based polyaniline electrodes can be rapidly self-charged to 1220 mV by a compressive force of 20 N. Meanwhile, the piezo-supercapacitor delivers a specific capacitance of 2407 mF cm −2 with a 101.2 % retention after 10,000 charge-discharge cycles. The piezo-supercapacitor harvests mechanical energy and outputs electrical energy with a total energy conversion efficiency of 44.72 %. The work provides an effective strategy to construct synchronously external field-responsive films with multifunctionalities for enhanced energy conversion in integrated power cells.