Bacterial-Derived, Compressible, and Hierarchical Porous Carbon for High-Performance Potassium-Ion Batteries

Abstract

Hierarchical-structure electrodes which are integrated with the merits of superior cycling stability and high rate performance are highly desired for energy storage in next-generation portable electronics. For the first time, we reported a compressible and hierarchical porous carbon nanofiber foam (CNFF) derived from sustainable and abundant biomaterial resources-bacterial cellulose for boosting the electrochemical performance of potassium-ion batteries (PIB). The CNNF free-standing electrode with a hierarchical porous three-dimensional (3D) structure demonstrated excellent rate performance and good cyclic stability in the extended cycling test. Specifically, in the rate performance test, the CNFF electrode delivered high reversible capacity of 240 and 202 mA h g-1 at current density of 50 and 200 mA g-1, respectively. At high current density of 1000 mA g-1, the CNNF electrode maintained a stable capacity of 157.9 mA h g-1 for 2000 cycles, which translates into an average capacity decay of 0.006 % per cycle. After cycling at 1000 mA g-1 for 2000 cycles, the CNNF electrode is able to maintain a capacity of 141.2 mA h g-1 at a current density of 2000 mA g-1 for another 1500 cycles and a capacity of 122.1 mA h g-1 at a current density of 5000 mA g-1 for an additional 1000 cycles. Furthermore, quantitative kinetics analysis has validated the capacitive- and diffusion-controlled charge storage contributions in the carbon foam materials. Our work will inspire the search for cost-effective and sustainable materials for potassium electrochemical energy storage.