A high-performance hybrid Mg^sup 2+^/Li+ battery based on hierarchical copper sulfide microflowers conversion cathode

• Published in: Electrochimica acta Vol. 263; p. 168
• Main Authors: Li, Ting, Qin, Aiqiong, Wang, Hongtao, Wu, Mengyi, Zhang, Yuyue, Zhang, Yujie, Zhang, Daohong, Xu, Fei
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier BV 10-02-2018
• Subjects: Batteries; Cathodes; Conversion; Copper converters; Copper sulfides; Dendritic structure; Electrodes; Electrolytes; Energy storage; Flux density; Nanostructured materials; Storage batteries; Storage systems
• ISSN: 0013-4686; 1873-3859

Hybrid Mg2+/Li+ batteries featuring dendrite-free Mg anode and Li-storage cathode are promising safe energy storage systems. However, improving the energy density remains a grand challenge due to the quite limited capacities of traditional Li-intercalation cathodes. To circumvent this limitation, a new type of conversion cathode for hybrid Mg2+/Li+ batteries, microflower-like Cu9S5, is reported herein. The Cu9S5 cathode is compatible with the dual-salt Mg2+/Li+ electrolyte, and delivers a high reversible capacity of 300 mAh g-1 at 50 mA g-1 via electrochemical conversion reaction, with 94% capacity retention over 100 cycles in hybrid Mg2+/Li+ batteries. The electrode also shows an outstanding rate capability providing 155 mAh g-1 at 1000 mA g-1 and a superior long-term cycleability over 1000 cycles. This excellent performance is attributed to the hierarchical architecture of Cu9S5 which facilitates the reversible conversion reactions and stabilizes the electrode structure during discharge/charge process. This work provides new insight for the nanostructure design of stable conversion electrodes, and opens a new avenue for building safe and high-performance hybrid Mg2+/Li+ batteries for practical applications.