Study on the electrochemical process of Li+/Na+ mixed organic dual-cation battery system

Organic materials have garnered significant attention due to abundant resources, recyclability, and ease of design. However, they are hampered in practical applications by poor conductivity and high solubility. Herein, a lithium metal battery is developed in this work, utilizing the cathode material polyanthraquinonyl sulfide (PAQS) doped with a trace of NaCl. Additionally, the ionic liquid lithium bis-trifluoromethanesulfonimide and lithium metal as the anode. Physicochemical characterizations utilizing Raman spectroscopy and X-photoelectron spectroscopy indicate that both Na+ and Li+ migrate within the cell, forming a dual-cation battery. In addition, the battery displays exceptional rate performance with a capacity of 86 mAh·g−1 at 20 C, which is more than triples the capacity without NaCl, and has excellent cycling performance. Moreover, it retains 98% capacity after 1000 cycles at 2 C with no significant degradation. This research offers an innovative strategy for developing a high-performance double-cation battery.