LaMnO3 nanocomposite double network hydrogel electrodes with enhanced electrochemical and mechanical performance for flexible supercapacitors

Flexible supercapacitors are of tremendous interest to power future wearable electronics. The performance of a flexible supercapacitor strongly depends on the properties of electrode materials. In addition to the electrochemical performance, flexible electrodes must be mechanically robust or even stretchable during operation. Electrically conductive hydrogels (ECHs) are an ideal framework for flexible electrode design and construction, owing to their three-dimensional conductive network, toughness, and scalable synthesis. In this work, we synthesized modified LaMnO3 (MLMO) perovskites with porous tubular skeleton structure by a typical sol-gel method, and integrated the MLMO nanoparticles into a double network (DN) hydrogel, where the MLMO perovskites are uniformly dispersed in polyacrylamide (PAM)/polyvinyl alcohol (PVA) matrixes. The mechanical properties of this new composite hydrogel dramatically increase, with a remarkable enhanced tensile strength of 1.81 MPa and a high breaking elongation of over 440%. In addition, the composite hydrogel electrode shows exceptional capacitive characteristics, including a high gravimetric specific capacitance of 392 F g− 1 (at 1 A/g) and robust cycling stability (90% capacitance retention over 10,000 cycles). Our manufacturing strategy opens the opportunity to design flexible and stretchable supercapacitors with ideal nanostructures and outstanding hydrogel electrodes.