PEDOT-engineered Bi2O3 nanosheet arrays for flexible asymmetric supercapacitors with boosted energy density†
Pseudocapacitive Bi2O3 is considered as a promising negative material on account of the advantage of high theoretical specific capacitance, but its capacitance is still limited by poor intrinsic electrical conductivity and poor ionic diffusion. Therefore, rationally engineering the surface and the structure are essential to decorate Bi2O3 with high capacitance. Here, we reported conductive PEDOT-engineered Bi2O3 nanosheet arrays (CC/Bi2O3@PEDOT NAs) constructed via a combined solvothermal and electrodeposition approach as high-performance negative electrodes. As-achieved CC/Bi2O3@PEDOT NAs present vertical and interconnected network architecture, which provid a huge surface to connect with the electrolyte and shorten the penetration pathways. Benefiting from the PEDOT-engineered surface, superior electrical conductivity and accelerated charge transport are obtained and thus, the electrode exhibits optimal areal capacitance of 1.7 F cm−2 at 10 mV s−1. Remarkably, maximum energy density of 1.2 mW h cm−3 (123 W h kg−1) is delivered at power density of 9.4 mW cm−3 for the constructed ASC device. This study provides a novel strategy to engineer Bi2O3 towards high capacitance; also, it may be applied to design other high-performance electrodes in the future.