Spinel Li<sub>4</sub>Mn<sub>5</sub>O<sub>12</sub> as 2.0 V Insertion Materials for Mg‐Based Hybrid Ion Batteries
Yuan Cen, Yuping Liu, Yan Zhou, Licheng Tang, Pengfei Jiang, Jiahong Hu, Qin Xiang, Bingbing Hu, Chuanlan Xu, Danmei Yu, Changguo Chen
Abstract
Abstract With the increasing demand for electrical energy storage, a new Mg−Li hybrid battery with Mg anode is regarded as a promising candidate because of low cost, high volumetric capacity, and dendrite‐free nature of the Mg anode. Nevertheless, the characteristics of low operation voltage and low energy density for Mg−Li hybrid batteries hinders their widespread application, owing to limited reversible cathodes. To overcome these issues, a highly reversible fast Li + insertion cathode with high voltage is an effective strategy to realize high‐energy‐density Mg−Li hybrid batteries. Herein, we develop the 2 V high‐voltage spinel Li 4 Mn 5 O 12 cathode material with unique nano‐/microspheres, using a novel low‐temperature method, offering a short Li‐diffusion path and sufficient transport channels for electrolyte penetration into the electrode. For the first time, we demonstrate the feasibility of the spinel Li 4 Mn 5 O 12 nano‐/microspheres with hierarchical architecture as a cathode for 2 V hybrid Mg−Li batteries. It exhibits a reversible specific capacity of 155 mAh g −1 and a long discharge voltage platform exceeding 2.0 V (vs. Mg / Mg 2+ ) coupled with high energy density of 326 Wh kg −1 at a current density of 0.1 C (1 C=163 mA g −1 ). Our results pave the way of constructing new hybrid Mg−Li batteries with high voltage and high energy density.