Valence Engineering Enhancing NH4 + Storage Capacity of Manganese Oxides

Tzu-Hao Lu; Chenghui Zeng; Haozhe Zhang; Xin Shi; Yanxia Yu; Xihong Lu

doi:10.1002/smll.202206727

Valence Engineering Enhancing NH₄ ⁺ Storage Capacity of Manganese Oxides

Small. 2023 Apr;19(14):e2206727. doi: 10.1002/smll.202206727. Epub 2023 Jan 2.

Authors

Tzu-Hao Lu¹, Chenghui Zeng², Haozhe Zhang¹, Xin Shi¹, Yanxia Yu^{1

3}, Xihong Lu^{1

3}

Affiliations

¹ MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, The Key Lab of Low-carbon Chem & Energy Conservation of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, P. R. China.
² College of Chemistry and Chemical Engineering, Research Center for Ultra Fine Powder Materials, Ministry of Education and Jiangxi's Key Laboratory of Green Chemistry, Jiangxi Normal University, Nanchang, 330022, P. R. China.
³ Key Laboratory of Advanced Batteries Materials for Electric Vehicles of China Petroleum and Chemical Industry Federation, School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, 710048, China.

PMID: 36592429
DOI: 10.1002/smll.202206727

Abstract

Ammonium ions (NH₄ ⁺ ), as non-metallic charge carriers, are attracting attention in aqueous batteries due to its low molar mass, element sufficiency, and non-toxicity. However, the host materials for NH₄ ⁺ storage are still limited. Herein, an oxygen defects-rich manganese oxide (MnO_2-x ) for NH₄ ⁺ storage are reported. The oxygen defects can endow the MnO_2-x sample with improved electric conductivity and low interface activation energy. The electrochemical reaction mechanism is also verified by using ex situ X-ray photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FT-IR), demonstrating the insertion and extraction of NH₄ ⁺ in the MnO_2-x by formation/breaking of a hydrogen bond. As a result, MnO_2-x delivers a high capacity of 109.9 mAh g^-1 at the current density of 0.5 A g^-1 and retention of 24 mAh g^-1 after 1000 cycles at the current density of 4 A g^-1 , outperforming the pristine MnO₂ sample.

Keywords: ammonium ion batteries; hydrogen bond; manganese oxide; oxygen vacancies.

Abstract

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