Utilizing the Mn(II) Dissolution‐Induced Vacancy for Optimum Mg <sup>2+</sup> Storage of Spinel Mn <sub>3</sub> O <sub>4</sub>
Zhongyu Pan, Jiang Zhou, Tingting Qin, Dong Wang, Fuxi Liu, Yang He, Qing Liang, Wei Zhang, Weitao Zheng
Abstract
Abstract Manganese‐based oxide can theoretically exert the multivalent advantages of an aqueous magnesium‐ion cathode due to its redox activity and abundant crystal structure. However, sluggish diffusion kinetics of Mg 2+ and Mn dissolution limit the rate performance and structure stability. Herein, we successfully utilize the notorious dissolution of Mn(II) tetrahedral site contributed vacancies for packaging optimum Mg 2+ storage of a popular spinel Mn 3 O 4 electrode. Such mechanism reverses the sluggish diffusion kinetics. Moreover, merited by the common ion effect and drug dissolution, a suitable preaddition of Mn 2+ to electrolyte inhibit Mn(III) dissolution and optimize the integrity of the spinel framework. Impressively, the cathode achieves a reversible capacity of 310 mAh g −1 and a stable cycle performance of 2000 cycles with 94.9% retention. Our research shows that reversible insertion/extraction at vacancies and effective stabilization of spinel framework is a powerful strategy to achieve Mg 2+ ion energy storage system with high rate performance and long lifespan.