Polypyrrole-decorated hierarchical carbon aerogel from liquefied wood enabling high energy density and capacitance supercapacitor

Carbon aerogels (CAs) from biomass have low energy density and specific capacitance due to underutilized structure, severely hindering their application in high-performance supercapacitors. Herein, we address this issue through a binary composite in which psudocapacitive polypyrrole (PPy) microparticles are in situ grown on the surfaces of hierarchical porous liquefied wood carbon aerogels (LWCA). The deposited pseudocapacitive PPy microparticles contributes to the high energy density and specific capacitance. The hierarchical structure of LWCA prevents aggregation of PPy microparticles and ensures rapid transfer of electrolyte ions. In three electrodes system, the optimized hybride capacitive LWCA-PPy-65 composite exhibites excellent capacitive performance of 421.45 F g−1 and cycle stability with 82.9% after 5000 cycles. In KOH electrolyte, the hybrid supercapacitor from LWCA-PPy-65 demonstrates a high energy density of 52.0 Wh kg−1 with a power density of 2012.8 W kg−1, and excellent cyclic performance of 92.81% retention after 5000 cycles at 5 A g−1. In H2SO4 electrolyte, the fabricated solid state supercapacitor displays prominent cyclic performance of 92.81% retention after 5000 cycles at 5 A g−1. Such three-dimensional biomass-based composite aerogels with high energy density and capacitance demonstrated a promising application prospect in energy storage devices.