Next‐Generation Activated Carbon Supercapacitors: A Simple Step in Electrode Processing Leads to Remarkable Gains in Energy Density. (7th March 2017)

• Record Type: Journal Article
• Authors: Hwang, Jee Y.; Li, Mengping; El‐Kady, Maher F.; Kaner, Richard B.
• Is Part Of: Advanced functional materials. Volume 27:Number 15(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-03-07
• Subjects: activated carbon -- high‐voltage cells -- lasers -- redox‐electrolytes -- supercapacitors; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201605745
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : The global supercapacitor market has been growing rapidly during the past decade. Today, virtually all commercial devices use activated carbon. In this work, it is shown that laser treatment of activated carbon electrodes results in the formation of microchannels that can connect the internal pores of activated carbon with the surrounding electrolyte. These microchannels serve as electrolyte reservoirs that in turn shorten the ion diffusion distance and enable better interaction between the electrode surfaces and electrolyte ions. The capacitance can be further increased through fast and reversible redox reactions on the electrode surface using a redox‐active electrolyte, enabling the operation of a symmetric device at 2.0 V, much higher than the thermodynamic decompostion voltage of water. This simple approach can alleviate the low energy density of supercapacitors which has limited the widespread use of this technology. This work represents a clear advancement in the processing of activated carbon electrodes toward the next‐generation of low‐cost supercapacitors. Abstract : Laser treatment of activated carbon electrodes results in micro‐channels that connect internal pores of activated carbon with the surrounding electrolyte. These micro‐channels serve as electrolyte reservoirs shortening the ion diffusion distance and enabling better interaction between electrode surfaces and electrolyte ions. The capacitance can be further increased through fast and reversible redox reactions using a redox active electrolyte.