Ultralight and robust carbon nanofiber aerogels for advanced energy storage

Abstract

Currently, it still remains a grand challenge to simultaneously enhance the mechanical and electrochemical properties of carbon materials for advanced energy storage and conversion. Herein, we reported the exploration of a carbon nanofiber aerogel with a unique spider-web-like 3D network structure based on the welding effect rather than interfibrous entanglements, via the carbonization of bacterial cellulose (BC) nanofibers assisted by surface carboxylation treatment. The as-prepared carbon aerogel had an ultralow density of ∼2.7 mg cm⁻³, and exhibited high flexibility (ε > 90%) and robust repetitive compressive duration (only a 3% decrease after 100 cycles at ε = 90%). Moreover, it showed a specific capacitance of 268 F g⁻¹ at 0.5 A g⁻¹, which was among the best values of self-supporting carbon materials ever reported. The as-constructed solid-state supercapacitors (SSSCs) achieved a specific capacitance of 104 F g⁻¹ at 0.5 A g⁻¹ with excellent rate performance and cycling stability, which were much higher than those of most carbon-based SSSCs ever reported. More interestingly, such SSSCs showed great potential to be applied as flexible energy storage devices.