Polymer versus Cation of Gel Polymer Electrolytes in the Charge Storage of Asymmetric Supercapacitors

Abstract

Gel polymer electrolytes (GPEs) are promising candidates for highly efficient flexible electrochemical energy storage devices as they reduce leakage and size of the device as well as improving versatility with varied choice of solvents, polymers, and ions. However, the electrochemical mechanisms governing supercapacitive charge storage using a varied choice of polymers and cations (PVA, PEG, PEO-based Na + and K + ) are not systematically evaluated. In this work, the role of GPEs on the charge storage mechanism of a flexible solidstate asymmetric supercapacitor fabricated using porous carbon as the cathode and SnO 2 −TiO 2 composite flower as the anode with various GPEs, viz., poly(vinyl alcohol), poly(ethylene oxide), poly(ethylene glycol)-NaOH, and KOH, is reported. The composite electrode greatly improves the ion transportation, and the GPEs provide interconnected ion transport channels. The as-fabricated porous carbon/GPE/composite electrode as a flexible asymmetric supercapacitor displays an increased specific capacitance (C S up to ∼42.3 F g −1 ) compared to aqueous electrolytes (up to ∼14.1 F g −1 ). Among the studied GPEs, the poly(ethylene oxide)-NaOH-based GPE showed higher C S than poly(vinyl alcohol)-NaOH and poly(ethylene glycol)-NaOH, as the former offered a high cation response under the charge/discharge process.

Electrolyte selection for supercapacitive devices: a critical review

“…or a conducting salt dissolved in a solvent. 180 Generally, gel polymer electrolytes have the highest ionic conductivity among these three types of solid-state electrolytes due to the presence of a liquid phase. Due to their high ionic conductivity, gel polymer electrolytes are currently dominating solid electrolyte-based SCDs, and the usage of solid polymer electrolytes (SPEs) is very limited.…”

Template Synthesis of a Heterostructured MnO2@SnO2 Hollow Sphere Composite for High Asymmetric Supercapacitor Performance

“…However, its energy density is lower than 10 Wh/kg owing to the narrow potential window. For the purpose of broadening the electrochemical window of the pseudocapacitor in an aqueous electrolyte (∼1.23 V), the concept of asymmetric supercapacitors is proposed. − …”

A Perspective on the Commercial Viability of Perovskite Solar Cells

“…[193][194][195] Given the intrinsic instability of halide perovskite, moisture ingression into the halide perovskite has to be inhibited, either through deploying a solid-state electrolyte or utilizing tunneling layers (conductive layers deposited between the PSCs and supercapacitor subcells). Solid-state electrolytes lowered the charge transport kinetics, [196][197][198][199] whereas tunneling layers increased the internal shunt resistance of the device. [200][201][202] An effective technique to mechanically separate both subcells while ensuring electronic connectivity is required.…”