Dual-Graphite Batteries with Flame-Retardant Electrolyte Solutions

Graphical Double time : It is demonstrated that the concentrated solution of 3 M LiPF 6 -ethyl methyl carbonate/trimethyl phosphate (7 : 3 by vol.) is also compatible with graphite negative and works well for full dual-graphite batteries. Although trimethyl phosphate (TMP)-based electrolyte solutions are effective to resist flames in non-aqueous electrical energy storage devices, they are usually not so compatible with Li-graphite negative electrodes. Herein, we solve this problem by increasing the concentration of LiPF 6 salt in the solution. A benchmark graphite negative electrode (MCMB, mesocarbon microbeads) can deliver a capacity over 325 mAh g −1 and maintain good cyclability in a solution of 3 M LiPF 6 -ethyl methyl carbonate (EMC)/TMP (7 : 3 by vol.). Moreover, our previous work has confirmed that the graphite positive electrode also works very well in the above solution. Therefore, this solution can cater to both anion-graphite and Li-graphite intercalation electrodes, which enables the construction of dual-graphite batteries (DGBs). There are some problems arising during the DGB operation, and corresponding strategies are proposed.