Carbon aerogels for electrochemical applications

Abstract

Carbon aerogels are highly-porous, electrically conductive materials with tunable micro- and mesoporosity as well as surface area and envelope density. Their properties are dictated from sol-gel process of their organic precursors and carbonization conditions. Due to their well adjustable properties, they became very attractive in many fields of applications, such as CO2 capture, catalyst in fuel cells, or as electrodes for supercapacitors and batteries. Energy and power-storage capability of supercapacitors are associated with the physical and chemical characteristics of carbon-based electrodes. Cyclic voltammetry and galvanostatic charge/discharge measurements demonstrate the good electrochemical performance of the supercapacitor with carbon aerogels. A specific capacitance of 21.8 F·g−1 at 2 A·g−1 and cycle durability of 87% over 10,000 cycles was observed due to the presence of dual mesopores. These dual mesopores result in an enhanced access to reaction sites and facilitate electrolyte ion transport. [1] Ultramicroporous (pores smaller 1 nm) carbon aerogels as conductive matrices embedding sulfur for cathode application in lithium–sulfur batteries are able to suppress the polysulfide shuttle effect, maintaining 80% (about 1000 mA·h·g(S)−1) and 70% (about 800 mA·h·g(S)−1) of the initial discharge capacity after 200 cycles at a rate of 0.3C in carbonate and ether-based electrolytes, respectively. At a faster rate of 2C in both electrolyte systems aerogel-based cathode can still deliver a discharge capacity of at least mA·h·g(S)−1. [2] The mesoporous carbon aerogels can be considered as promising cathode catalysts for application in polymer electrolyte membrane fuel cells. The platinum free carbon aerogels contain catalytic active Fe-Nx sites and demonstrate suitable microstructure for enhanced electrocatalytic performance. 1. Park, D.-W., et al., A dual mesopore C-aerogel electrode for a high energy density supercapacitor. Current Applied Physics, 2016. 16(6): p. 658-664. 2. Nojabaee, M., et al., Ultramicroporous carbon aerogels encapsulating sulfur as the cathode for lithium–sulfur batteries. Journal of Materials Chemistry A, 2021. 9: p. 6508-6519.