Interfacial thermodynamics-inspired electrolyte strategy to regulate output voltage and energy density of battery chemistry

Shan Guo; Jialin Li; Baoshan Zhang; Wenyong Chen; Guozhao Fang; Mengqiu Long; Shuquan Liang

doi:10.1016/j.scib.2021.10.016

Interfacial thermodynamics-inspired electrolyte strategy to regulate output voltage and energy density of battery chemistry

Sci Bull (Beijing). 2022 Mar 30;67(6):626-635. doi: 10.1016/j.scib.2021.10.016. Epub 2021 Oct 23.

Authors

Shan Guo¹, Jialin Li², Baoshan Zhang¹, Wenyong Chen¹, Guozhao Fang³, Mengqiu Long⁴, Shuquan Liang⁵

Affiliations

¹ School of Materials Science and Engineering, Central South University, Changsha 410083, China.
² School of Physics and Electronics, Central South University, Changsha 410083, China.
³ School of Materials Science and Engineering, Central South University, Changsha 410083, China; Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha 410083, China. Electronic address: fg_zhao@csu.edu.cn.
⁴ School of Physics and Electronics, Central South University, Changsha 410083, China. Electronic address: mqlong@csu.edu.cn.
⁵ School of Materials Science and Engineering, Central South University, Changsha 410083, China; Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha 410083, China. Electronic address: lsq@csu.edu.cn.

PMID: 36546124
DOI: 10.1016/j.scib.2021.10.016

Abstract

The electrochemical behaviors of battery chemistry, especially the operating voltage, are greatly affected by the complex electrode/electrolyte interface, but the corresponding basis understanding is still largely unclear. Herein, the concept of regulating electrode potential by interface thermodynamics is proposed, which guides the improvement of the energy density of Zn-MnO₂ battery. A cationic electrolyte strategy is adopted to adjust the charge density of electrical double layer, as well as entropy change caused by desolvation, thus, achieving an output voltage of 1.6 V (vs. Zn²⁺/Zn) and a capacity of 400 mAh g^-1. The detailed energy storage behaviors are also analyzed in terms of crystal field and energy level splitting. Furthermore, the electrolyte optimization benefits the efficient operation of Zn-MnO₂ battery by enabling a high energy density of 532 Wh kg^-1 based on the mass of cathode and a long cyclic life of more than 500 cycles. This work provides a path for designing high-energy-density aqueous battery via electrolyte strategy, which is expected to be extended to other battery systems.

Keywords: Electrolyte strategy; Energy density; Energy level splitting; Interfacial thermodynamics; Voltage regulation.