title: Carbon with ultrahigh capacitance when graphene paper meets K3Fe(CN)6.
abstract: For the first time, we have shown a novel supercapacitor system with a graphene paper electrode in the redox-electrolyte of K3Fe(CN)6 based on the system-level design principle. By combining electric double-layer capacitance and pseudocapacitance, the specific capacitance could be increased 5-fold compared with the conventional electrode-electrolyte system. This large improvement is attributed to the additional redox reactions on the graphene paper electrode via the constituent ions of K3Fe(CN)6 in the redox-electrolyte, during which the discharge process is highly enhanced. More importantly, the potential interval could reach as high as 1.6 V beyond the limited operating voltage of water (∼1.23 V). After 5000 continuous cycles, 94% of the initial capacitance was retained. The newly designed novel supercapacitor system is binder-free, conducting additive-free and can deliver higher capacitance. This designed graphene-paper-electrode/redox-electrolyte system can provide a versatile strategy for high-capacitance supercapacitor systems.
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China. dongfeng@ciac.ac.cn.
authors.forename: Kunfeng
authors.initials: K
authors.lastname: Chen
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Xue
authors.forename: Sridhar
authors.initials: S
authors.lastname: Komarneni