Maximization of Spatial Charge Density: An Approach to Ultrahigh Energy Density of Capacitive Charge Storage

Hongyun Ma; Hongwu Chen; Mingmao Wu; Fengyao Chi; Feng Liu; Jiaxin Bai; Huhu Cheng; Chun Li; Liangti Qu

doi:10.1002/anie.202005270

Maximization of Spatial Charge Density: An Approach to Ultrahigh Energy Density of Capacitive Charge Storage

Angew Chem Int Ed Engl. 2020 Aug 17;59(34):14541-14549. doi: 10.1002/anie.202005270. Epub 2020 Jul 7.

Authors

Hongyun Ma¹, Hongwu Chen¹, Mingmao Wu¹, Fengyao Chi¹, Feng Liu², Jiaxin Bai³, Huhu Cheng³, Chun Li¹, Liangti Qu^{1

3}

Affiliations

¹ Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China.
² State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
³ Key Laboratory for Advanced Materials Processing Technology, Ministry of Education of China, State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, P. R. China.

PMID: 32506611
DOI: 10.1002/anie.202005270

Abstract

Capacitive energy storage has advantages of high power density, long lifespan, and good safety, but is restricted by low energy density. Inspired by the charge storage mechanism of batteries, a spatial charge density (SCD) maximization strategy is developed to compensate this shortage by densely and neatly packing ionic charges in capacitive materials. A record high SCD (ca. 550 C cm^-3 ) was achieved by balancing the valance and size of charge-carrier ions and matching the ion sizes with the pore structure of electrode materials, nearly five times higher than those of conventional ones (ca. 120 C cm^-3 ). The maximization of SCD was confirmed by Monte Carlo calculations, molecular dynamics simulations, and in situ electrochemical Raman spectroscopy. A full-cell supercapacitor was further constructed; it delivers an ultrahigh energy density of 165 Wh L^-1 at a power density of 150 WL^-1 and retains 120 Wh L^-1 even at 36 kW L^-1 , opening a pathway towards high-energy-density capacitive energy storage.

Keywords: capacitive energy storage; in situ Raman spectroscopy; ion sieving effect; spatial charge density; zinc ion hybrid capacitor.

Abstract

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