A Magnesium/Lithium Hybrid-Ion Battery with Modified All-Phenyl-Complex-Based Electrolyte Displaying Ultralong Cycle Life and Ultrahigh Energy Density.

Ding, Yingyi; Han, Tianli; Wu, Zhao; Guan, Yong; Hu, Jun; Hu, Chaoquan; Tian, Yangchao; Liu, Jinyun · ACS Nano · 2022

basic_science · Level V

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Abstract

Magnesium/lithium hybrid-ion batteries (MLHBs) combine the advantages of high safety and fast ionic kinetics, which enable them to be promising emerging energy-storage systems. Here, a high-performance MLHB using a modified all-phenyl complex with a lithium bis(trifluoromethanesulfonyl)imide electrolyte and a NiCo<sub>2</sub>S<sub>4</sub> cathode on a copper current collector is developed. A reversible conversion involving a copper collector with NiCo<sub>2</sub>S<sub>4</sub> efficiently avoids the electrolyte dissociation and diffusion difficulties of Mg<sup>2+</sup> ions, enabling low polarization and fast redox, which is verified by X-ray absorption near edge structure analysis. Such combination affords the best MLHB among all those ever reported, with a reversible capacity of 204.7 mAh g<sup>-1</sup> after 2600 cycles at 2.0 A g<sup>-1</sup>, and delivers an ultrahigh full electrode-basis energy density of 708 Wh kg<sup>-1</sup>. The developed MLHB also achieves good rate performance and temperature tolerance at -10 and 50 °C with a low electrolyte consumption. The hybrid-ion battery system presented here could inspire a broad set of engineering potentials for high-safety battery technologies and beyond.