Top-down strategy for constructing cellulose skeleton-derived high-performance supercapacitors with oxidation resistance

Lignin-removed cellulose skeleton (CS) with porous structure and abundant oxygen-containing groups synergized with functional MXene is a promising strategy for constructing high-performance energy storage electrodes. However, the intrinsic instability of MXene under environmental conditions poses a significant challenge to the advancement of MXene-CS (MCS) electrodes. Herein, Polypyrrole@MXene-CS (PPy@MXene-CS, PMCS) electrodes with excellent antioxidant and electrochemical performances are developed by constructing PPy-encapsulated MXene on CS through impregnation and in-situ loading. The impregnated MXene is tightly bound to CS through hydrogen bonding interactions to form the homogeneous MCS conductive network. The in-situ encapsulated PPy not only strengthens the oxidation resistance of MXene, but also imparts the PMCS additional pseudocapacitance. Benefiting from the natural CS pore structure and the synergistic electrochemical energy storage materials, the PMCS electrode demonstrates an area capacitance of up to 2622 mF cm −2 (at 3 mA cm −2 current density) and without significant degradation after two months storage. The assembled quasi-solid-state symmetric supercapacitor exhibits the satisfactory area capacitance (2144.5 mF cm −2 at 3 mA cm −2 ), energy density (21.6 μWh cm −2 ) and cycling capability (93.2 % capacitance retention after 6000 cycles). This work presents a breakthrough strategy for fabricating high-performance and oxidation-resistant CS electrodes, paving the way for advanced energy storage technologies.