PUB-2016-ASW

Asymmetric supercapacitors with metal-like ternary selenides and porous graphene electrodes

​Chuan Xia, Qiu Jiang, Chao Zhao, Pierre M. Beaujuge, Husam N. Alshareef, "Asymmetric supercapacitors with metal-like ternary selenides and porous graphene electrodes​"
​Nano Energy, Volume 24, June 2016, Pages 78–86
Chuan Xia, Qiu Jiang, Chao Zhao, Pierre M. Beaujuge, Husam N. Alshareef
Nickel cobalt selenide, Porous graphene film, Asymmetric supercapacitor, High conductivity
2016
​Asymmetric supercapacitors provide a promising approach to fabricate capacitive energy storage devices with high energy and power densities. In this work, asymmetric supercapacitors with excellent performance have been fabricated using ternary (Ni, Co)0.85Se on carbon fabric as binder-free positive electrode and porous free-standing graphene film as negative electrode. Owing to their metal-like conductivity (1.67 106 S m1 ), significant electrochemical activity, and superhydrophilic nature, our nanostructured ternary nickel cobalt selenides result in a much higher areal capacitance (2.33 F cm2 at 4 mA cm2 ), better rate performance and cycling stability than their binary selenide equivalents, and other ternary oxides and chalcogenides. Those hybrid supercapacitors can afford impressive areal capacitance and stack capacitance of 529.3 mF cm2 and 6330 mF cm3 at 1 mA cm2 , respectively. More impressively, our optimized asymmetric device operating at 1.8 V delivers a very high stack energy density of 2.85 mW h cm3 at a stack power density of 10.76 mW cm3 , as well as 85% capacitance retention after 10,000 continuous charge–discharge cycles. Even at a high stack power density of 1173 mW cm3 , this device still deliveries a stack energy density of 1.19 mW h cm3 , superior to most of the reported supercapacitors.