Enhancing graphene-based supercapacitors with plasma methods: A review

Graphene aerogels (GAs) have emerged as promising materials for supercapacitor applications, yet traditional methods often fall short of achieving optimal surface modifications for enhanced electrochemical properties. The focus of the review is to explore the current techniques used in plasma treatment for GA, how these are effective, what can be done to improve the technology, and what further research is required to advance the field. Particular attention is given to oxygen and nitrogen plasma treatments, which have shown significant improvements in specific capacitance and cycling stability. Hydrogen plasma treatment assimilates hydrogen atoms into graphene, potentially augmenting chemical reactivity and charge transfer. The introduction of nitrogen into graphene through plasma treatment results in the incorporation of nitrogen atoms, which causes changes in the electrical and mechanical characteristics of the material. This can lead to higher capacitance and enhanced cycling stability, which means improved retention after charge-discharge cycles. The existing techniques are primarily focused on reduced graphene oxide and other graphene fibers or GA, but the studies are minimal, and a consensus on the overall reliability in achieving high capacitance is also seen to be less precise. This work proposes future directions to facilitate the development of high-performance, plasma-treated GA supercapacitors.