Affiliation:
1. School of Physics and Electronic Engineering Jiangsu University Zhenjiang 212013 P. R. China
2. Institute of Laser & Optoelectronic Intelligent Manufacturing Wenzhou University Wenzhou 325035 P. R. China
3. Sinosteel New Materials Co., Ltd Sinosteel Nanjing Advanced Materials Research Institute Co., Ltd Maanshan 243000 P. R. China
Abstract
AbstractFree‐standing micro‐supercapacitor (MSC) devices without substrate or current collectors are promising for practical applications. However, it is still difficult to prepare high‐performance free‐standing MSC devices because of the requirement of optimized active sites, conductivity, ion diffusion, controlled patterns, moisture susceptibility, etc. Here, it is proposed that the optimization of oxygen level on graphene is promising to solve these requirements because of the balance of sp2 and sp3 hybridization. Using the medium‐oxidized graphene, the flexible, conductive, hydro‐stable, easy‐processing film can be facilely obtained, which facilitates the preparation of free‐standing MSC electrodes. After constructing with gel electrolyte, the free‐standing MSC device shows a high capacitance of 898.4 mF cm−2 using aqueous‐gel electrolyte and 383.6 mF cm−2 using ion‐gel electrolyte with mass loading of ca. 10 mg cm−2. Correspondingly, the MSC device can achieve a landmark energy density of 42.6 µWh cm−2 at 0.85 mW cm−2 (7.1 mWh cm−3 at 141.7 mW cm−3). The advantages of high performance, facile preparation, and low inactive components make the free‐standing MSC device promising for practical applications.
Funder
National Natural Science Foundation of China