A Metal-free Battery with Pure Ionic Liquid Electrolyte

Metal or metal-ion-based batteries represent the mainstream battery technology, in which metal ions either participate in the electrode redox reaction or act as the charge carrier in the electrolyte. The principle guides battery designs and leads to the most widely adopted battery construction of metal-ion acceptor/metal salt in solvent/metal-ion donor. Although these architectures have seen significant progress, there are still many issues with them, including dendrite growth, solid-electrolyte interface corruption, and safety concerns. In this article, the intercalation/deintercalation of organic cations other than metal ions is explored in an all-organic battery composed of organic anode/cathode and pure ionic liquid electrolyte. This metal-free and solvent-free concept has been demonstrated by polyimide/1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/polytriphenylamine full-cell, through which capacity near theoretical value, more than 5,000 cycling life, rate capability up to 200 C, and remarkable low-temperature performance has been achieved. Our work provides an alternate way of developing future efficient, safe, green, and versatile batteries.