High-capacity pseudocapacitive Li storage on functional nanoporous carbons with parallel mesopores

Pseudocapacitive storage of monovalent alkali cations, such as Li+ and Na+, is critically important for the development of metal-ion capacitors. Functional carbon materials decorated with ketone-containing groups are excellent candidates for this purpose. An epoxidation approach was deployed in this work to decorate electroactive oxygen groups on a high surface area nanoporous carbon with aligned mesopores. Because of the turbostratic structure, the intermediate epoxides dissipated into double-bonded oxygen groups in the functionalized carbon. The synergy of large porosity, good conductivity and enhanced surface redox activity endows the functionalized carbon cathode with high capacity (313 mA h/g@50 mA/g), good stability (>200 cycles) and high rate capability (148 mA h/g@400 mA/g).

Graphical abstractThrough epoxidation, an oxidized nanoporous carbon cathode with extraordinary pseudocapacitive Li-storage capacity was fabricated. The cathode showed improved rate performance as well as long-term stability that are beneficial for high power lithium ion capacitors.Figure optionsDownload full-size imageDownload as PowerPoint slide