The role of polymer gel electrolyte infiltration for enhancement of capacitance and cycle stability

• A new type [EMIM][TFSI]/PPC/PC polymer gel electrolyte is developed. • Activated carbon (AC) coated electrodes-based pouch cell (5 cm × 5 cm) supercapacitor is fabricated. • [EMIM][TFSI]/PPC/PC showed high voltage (>2.6 V) performance with maximum capacitance of 5.81 f. • Infiltration effect of this electrolyte improves the capacitance and cycle stability. • [EMIM][TFSI] /PPC /PC electrolyte can be used for future structure integrated energy storage for aerospace and aircraft. With the increasing application of electronic materials in various fields such as flexible electronic textiles, wearable and portable gadgets, aerospace and aircraft systems etc., the demand for clean high-power energy storage devices is also increasing rapidly. To date, the application of market available supercapacitors has not met the energy expectations in the range of market leading Li-ion batteries (LIBs) due to their unreliable mechanical flexibility, electrolyte leakage, low voltage application, low capacity, low cycle stability and moderate rate-capability. Inappropriate utilization of the maximum porosity of the electrode material and inefficient activities of the electrode/electrolyte interface are major challenges for present supercapacitor development. In this work, for the first time, the role of polymer gel electrolyte infiltration to improve the electrochemical performance of a supercapacitor has been explicitly studied and investigated. It has been observed that 1-Ethyl-3- Methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][TFSI] ionic liquid electrolyte embedded in Polypropylene Carbonate (PPC) and Polycarbonate (PC) polymer matrix polymer gel electrolyte (PGE) showed excellent supercapacitive performance at high voltage window 2.6 V by delivering maximum total capacitance of 5.81 F and maximum energy density 10.9 Wh kg -1 at 30 mA current (0.06 A g -1 ). Regular infiltration of the polymer gel electrolyte inside the electrode material is also observed during long cycle operation of 10,000 cycles. Infiltration of electrolyte ions into the pores of electrode materials plays a significant role in increasing capacitance and cycle Stability. These results highlight the potential of this novel high-voltage polymer gel electrolyte for future high-power energy storage device applications.