标题：Printable magnesium ion quasi-solid-state asymmetric supercapacitors for flexible solar-charging integrated units
作者：Zhengnan Tian1, Xiaoling Tong1, Guan Sheng2, Yuanlong Shao2, Lianghao Yu1, Vincent Tung2, Jingyu Sun1,3, Richard B. Kaner4 & Zhongfan Liu1,3,5
单位：1. College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, 215006 Suzhou, P. R. China
2. College Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
3. Beijing Graphene Institute (BGI), 100095 Beijing, P. R. China
4. Department of Chemistry and Biochemistry, Department of Materials Science and Engineering, and California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA
5. Center for Nanochemistry (CNC), College of Chemistry and Molecular Engineering, Peking University, 100871 Beijing, P. R. China
摘要：Wearable and portable self-powered units have stimulated considerable attention in both the scientific and technological realms. However, their innovative development is still limited by inefficient bulky connections between functional modules, incompatible energy storage systems with poor cycling stability, and real safety concerns. Herein, we demonstrate a flexible solar-charging integrated unit based on the design of printed magnesium ion aqueous asymmetric supercapacitors. This power unit exhibits excellent mechanical robustness, high photo-charging cycling stability (98.7% capacitance retention after 100 cycles), excellent overall energy conversion and storage efficiency (ηoverall = 17.57%), and outstanding input current tolerance. In addition, the Mg ion quasi-solid-state asymmetric supercapacitors show high energy density up to 13.1 mWh cm−3 via pseudocapacitive ion storage as investigated by an operando X-ray diffraction technique. The findings pave a practical route toward the design of future self-powered systems affording favorable safety, long life, and high energy.