Flexible Electrochromic Supercapacitors With CuS-based Hybrid Films As The Transparent Conductive Electrodes

The proposition of a concept of multifunctional smart glass,which can change its color and simultaneously store energy,meets the demand of multifunctional devices and points out the direction of electrochromic devices.We hope to find a new conducting electrode that are highly transparent,flexible,conductive,and chemically stable to promote the development of electrochromic supercapacitors.The purpose of this paper is to prepare a new flexible and transparent conductive electrode and to explore its application in electrochromic supercapacitors.By using photolithography,chemical vapor deposition and a low temperature solvothermal reaction methods,we chose CuS as the conductors to fabricate the conductive films with percolating periodic lines,in which the frameworks can conduct current and leave large empty spaces that render the film transparent.Due to the size of the spaces,they cannot be regarded as continuous electrodes for some applications.After applying a graphene layer above,we obtained continuously conductive graphene/CuS networks(G-CuS)electrodes.Rational designs render efficient performances.We measured their optoelectronic,mechanically and chemically stable performances.At room temperature,they achieve a sheet resistance(RS)as low as 20.2 Ω/sq with the high transmittance of over 85%.In addition,they display a remarkable mechanical flexibility with a small increase of～10 Ω2/sq after 1000 bending cycles.Excellent chemical stabilities under electrodeposition of polyaniline(PANI)and cyclic tests of cyclic voltammetry and galvanostatic charge-discharge of PANI/G-CuS electrodes are achieved as well.In particular,when used as the transparent conductive electrodes of PANI,PANI/G-CuS electrodes showed excellent electrochromism(CE=24.91cm2 C-1),supercapacity(5 mV s-1,8.606 mF cm-2;0.025 mA cm-2,17.3 mF cm-2)and integrated multifunctional electrochromo-supercapacity,which demonstrate the feasibility of G-CuSfilms as the transparent conductive electrodes in electrochromic supercapacitors.