Surface-Induced Desolvation of Hydronium Ion Enables Anatase TiO2 as an Efficient Anode for Proton Batteries

Chao Geng; Tulai Sun; Zhencui Wang; Jin-Ming Wu; Yi-Jie Gu; Hisayoshi Kobayashi; Peng Yang; Jianhang Hai; Wei Wen

doi:10.1021/acs.nanolett.1c02421

Surface-Induced Desolvation of Hydronium Ion Enables Anatase TiO₂ as an Efficient Anode for Proton Batteries

Nano Lett. 2021 Aug 25;21(16):7021-7029. doi: 10.1021/acs.nanolett.1c02421. Epub 2021 Aug 9.

Authors

Chao Geng¹, Tulai Sun², Zhencui Wang¹, Jin-Ming Wu³, Yi-Jie Gu⁴, Hisayoshi Kobayashi⁵, Peng Yang¹, Jianhang Hai¹, Wei Wen¹

Affiliations

¹ College of Mechanical and Electrical Engineering, Hainan University, Haikou 570228, China.
² Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
³ State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
⁴ College of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China.
⁵ Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.

PMID: 34369781
DOI: 10.1021/acs.nanolett.1c02421

Abstract

Hydrogen ion is an attractive charge carrier for energy storage due to its smallest radius. However, hydrogen ions usually exist in the form of hydronium ion (H₃O⁺) because of its high dehydration energy; the choice of electrode materials is thus greatly limited to open frameworks and layered structures with large ionic channels. Here, the desolvation of H₃O⁺ is achieved by using anatase TiO₂ as anodes, enabling the H⁺ intercalation with a strain-free characteristic. Density functional theory calculations show that the desolvation effects are dependent on the facets of anatase TiO₂. Anatase TiO₂ (001) surface, a highly reactive surface, impels the desolvation of H₃O⁺ into H⁺. When coupled with a MnO₂ cathode, the proton battery delivers a high specific energy of 143.2 Wh/kg at an ultrahigh specific power of 47.9 kW/kg. The modulation of the interactions between ions and electrodes opens new perspectives for battery optimizations.

Keywords: Crystal plane engineering; Desolvation effect; Energy storage; Hydrogen ion batteries; Titanium dioxide.