Authors: Tzu‐Hao Lu, Chenghui Zeng, Haozhe Zhang, Xin Shi, Yanxia Yu, Xihong Lu
Published: 2023-01-02
Source: Full article
AbstractAmmonium 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 (MnO2–x) for NH4+ storage are reported. The oxygen defects can endow the MnO2–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 MnO2–x by formation/breaking of a hydrogen bond. As a result, MnO2–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.