Recent progress in the development of anodes for asymmetric supercapacitors

Asymmetric supercapacitors (ASCs) have great promise as an alternative power source in portable electronics and hybrid vehicles. To date, the imbalance between the developments of anode and cathode materials for ASCs remains a crucial issue, which makes the development of high-performance anodes a significant research direction. In this article, we review recent achievements in the design and fabrication of novel ASC anodes, which fall into the categories of carbon based, metal oxides based, metal nitrides based, and other anodes. The merits and demerits of these anodes are analyzed and discussed based on the results published in the literature in the past few years. The strategies employed to overcome the specific drawbacks of various anode materials are elaborated. Moreover, the electrochemical performances of ASC devices assembled with these anodes are critically examined and compared. Finally, we further project the trends and challenges in the future development of high-performance ASC anodes.