Biotemplate synthesis of polypyrrole@bacterial cellulose/MXene nanocomposites with synergistically enhanced electrochemical performance

Polypyrrole (PPy) has received extensive attention in supercapacitor electrodes due to its promising electrochemical activity, while the poor cycling stability and densely packed structure limited its electrochemical performance. Herein, we demonstrate the fabrication of flexible and freestanding PPy@bacterial cellulose (BC)/MXene composite film with significantly enhanced electrochemical performance. PPy nanoparticles were uniformly deposited on BC nanofibers via in situ polymerization, and assembled with highly conductive MXene (Ti 3 C 2 T x ) nanoflakes through strong interfacial interactions. BC as a biological template can effectively disperse PPy nanoparticles. The intercalation of PPy@BC nanofibers into Ti 3 C 2 T x layers constructs hierarchically packed nanofibrous structure, which provides extensive accessible electrochemical active sites. Freestanding PPy@BC/Ti 3 C 2 T x (PBM) electrode exhibits superior specific capacitance (gravimetric and areal capacitance of up to 550 F g −1 and 879 mF cm −2 , respectively) and excellent capacitance retention of 83.5% after 10,000 cycles. In addition, the symmetric supercapacitor assembled by PBM papers present a high energy density of 33.1 W h kg −1 (power density of 243 W kg −1 ) and excellent capacitance retention. The elaborately designed nanostructure and PPy-Ti 3 C 2 T x hybridization make great contribution to the enhanced electrochemical performance, which provide a feasible method for the fabrication of conductive polymer-based high-performance flexible supercapacitor electrodes. Graphic abstract