Ultra-fine MnO₂ nanoparticle-decorated three-dimensional interconnected bacterial cellulose carbon nanofibers with enhanced electrochemical performance derived from assisted liquid-phase plasma electrolysis

Transition metal oxide, manganese dioxide (MnO₂) is recognized as a promising electrode material of supercapacitor with high theoretical capacity. However, its shortcomings such as poor cyclic stability and low actual specific capacitance hinder its practical application, and the conventional synthesis process is complicated and the synthesis time is long. Herein, this paper introduces a novel assisted liquid-phase plasma electrolysis technique, which has realized the simple and rapid synthesis of MnO₂ nanoparticle-decorated bacterial cellulose nanofibers (BCNF/MnO₂) composites. BCNF forms a highly conductive interconnected three-dimensional network with ultra-fine MnO₂ nanoparticles (10–20 nm) uniformly distributed on its surface. This structure provides the BCNF/MnO₂ composites with excellent electrochemical performance, achieving a specific capacitance of 253 F g⁻¹ at 0.5 A g⁻¹. The assembled asymmetric supercapacitor achieves a specific capacitance of 92 F g⁻¹ at 0.2 A g⁻¹, and displays an energy density of 51.1 Wh·kg⁻¹ at power density of 200 W kg⁻¹. In addition, over the 5000 cycles, the capacitance loss rate of BCNF//BCNF/MnO₂ device is only 6.2 %. More importantly, this work offers an innovative and efficient route for one-step synthesis and potential commercial applications of carbon-based MnO₂ composites as the energy storage materials.