title: Promoting power density by cleaving LiCoO2into nano-flake structure for high performance supercapacitor.
abstract: LiCoO2(LCO) usually can deliver high energy density but low power density in Li-ion batteries (LIBs). Whether LCO could be used as electrode material for high-performance supercapacitors is dependent on promoting its power density. Owing to Faradaic redox reactions taking place on its surfaces or inside crystals through ion intercalation/deintercalation from the surfaces, increasing the specific area of LCO is a key factor to promote its rate capability. Herein, we report a facile strategy to prepare LCO nano-flakes with high specific area exceeding that of currently used micro-scale particles in LIBs. LCO as a nano-flake structure is expected to have a high fraction of Li atom exposure, which benefits fast redox reactions taking place on the surfaces. An LCO-based electrode exhibits an excellent specific capacitance of 581.3 F g-1at 0.5 A g-1, high power density of 2262 W kg-1at an energy density of 41.0 Wh kg-1, and good cycling stability (83.9% capacitance retention at 6 A g-1after 2000 cycles) in LiCl aqueous electrolyte. Faradaic redox behaviors have been analyzed, indicating an ideal diffusion-controlled process. Moreover, a full solid-state symmetric supercapacitor is assembled using LCO nano-flake-based electrodes, which presents good performance with light weight and flexibility. Impressively, three charged supercapacitors in series can light 100 green light emitting diodes for 14 min. LCO in nano-flake structure form with high power density could be an excellent material for superior supercapacitors.
authors.affiliation: Department of Applied Physics, The State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, P. R. China. hucg@cqu.edu.cn.
authors.forename: Qipeng
authors.initials: Q
authors.lastname: Liu
authors.forename: Muhammad Sufyan
authors.initials: MS
authors.lastname: Javed
authors.forename: Cuilin
authors.initials: C
authors.lastname: Zhang
authors.forename: Yanrong
authors.initials: Y
authors.lastname: Li
authors.forename: Chenguo
authors.initials: C
authors.lastname: Hu
authors.forename: Chengshuang
authors.initials: C
authors.lastname: Zhang
authors.forename: Meihui
authors.initials: M
authors.lastname: Lai
authors.forename: Qi
authors.initials: Q
authors.lastname: Yang