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Abstract: Bacterial cellulose (BC) was used as a raw material to produce freestanding carbon aerogels (CAs). The CAs were further decorated with Ni and MnO2/Ni(OH)2 hybrid via electrodeposition and redox reaction to produce carbon nanofiber networks decorated with electrochemically active metal and metal compounds. The properties of this novel material as supercapacitor electrodes were investigated. The electrochemical performance of the electrodes was examined in 1 M Na2SO4 electrolyte using cyclic voltammetry (CV), cyclic charge-discharge (CCD), and electrochemical impedance spectroscopy (EIS) tests. The results showed that a specific capacitance of 109 F g−1 was achieved at the current density of 1 A g−1. The electrodes could deliver an energy density of 9.4 Wh kg−1 and a power density of 4 KW kg−1 and demonstrated a high cyclability. These results showed great potential of this new material for supercapacitor electrodes. A flexible solid-state supercapacitor prototype was prepared using this material to demonstrate its function as a power source for a LED light. This study provided a new way to use BC as a biobased low-cost material for the fabrication of energy storage devices.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Bubbles evolving from electrode surface are the results of the multi-processes, interfacial mass transfer, chemical reaction, micro fluid flow, etc. In this paper, the investigations on the bubble growth mechanism during photoelectrochemical and electrochemical conversions are carried out. The experimental results show two different growth laws during photoelectrochemical and electrochemical conversions, which are chemical reaction and diffusion controlled respectively, caused by the difference in the effective surface area of the electrode. And mathematical models for bubble growth describing the two effects are established. [ABSTRACT FROM AUTHOR]