N,O-codoped porous carbon nanosheets for capacitors with ultra-high capacitance

Abstract

Significant enhancement of energy density of electrical double layered capacitors is a major challenge for electrochemical capacitors to conquer the emerging field of large scale renewable energy storage. The enhancement of specific capacitance is an effective strategy to obtain higher energy density. Addition of redox mediator in the electrolyte as pseudocapacitive sources could enhance the specific capacitance, but well-coupled electrode materials should be developed as well. Herein, as a proof-of-concept experiment, N, O-codoped porous carbon nanosheets have been fabricated, wherein graphene oxide is employed as both oxygen source as well as structure directing agent. Unexpectedly, the obtained electrode materials endow electrical double layered capacitors with excellent capacitive performances, including the ultra-high specific capacitance (5073.5 F g−1) and excellent cycling stability, which could be attributed to the synergy of morphology and surface chemistry of N, O-codoped porous carbon nanosheets. These results would form the basis for an unprecedented perspective in the development of next generation electrode materials for electrical double layered capacitors.