Reduced water activity in co-solvent electrolyte enables 2 V zinc-ion hybrid capacitors with prolonged stability and high energy density

Abstract

Aqueous Zn-ion hybrid capacitor (ZIC) is a promising energy storage device owing to the cost-benefit and intrinsic safety conferred by the energy-dense Zn anode and capacitor-type cathode in aqueous electrolytes....

A new selection criterion for voltage windows of aqueous zinc ion hybrid capacitors: achieving a balance between energy density and cycle stability

“…4(c), the coverage of the cathode carbon material surface with a dense layer of basic zinc sulfate increased the HER free energy when compared with the carbon material without coverage by basic zinc sulfate, indicating the occurrence of less reaction. 9 Therefore, the dense basic zinc sulfate covering the surface of the cathode carbon material not only reduced the local H + concentration due to the slightly alkaline environment required for its formation but instead hindered the HER by hindering the diffusion of H + to the electrode material surface for the HER occurrence (Fig. 4(d) and (f), and Video S1 †).…”

“…Moreover, the use of ZHSs allows for a wider voltage window, leading to higher energy density than normal capacitors. 9 Therefore, many studies have focused on ZHSs, and many groundbreaking results have been achieved. For instance low-temperature energy storage devices, 10 the systematic tailoring of carbon microstructures to optimize supercapacitive activity, 11 and flexible wearable ZHSs 12 have been reported.…”

Non-Aqueous Zn-Ion Hybrid Supercapacitors: Acetonitrile vs Propylene Carbonate Based Electrolyte

“…Superior cycling stability of the ZIHS was demonstrated to that of the aqueous ZIHS when tested under realistic conditions in the potential range of 0.2-1.8 V. Further extending the operating potential of the ZIHS to 2 V enabled an increase of 72.2% and 68.3% in capacity and energy density, respectively. 25 The deep eutectic solvent containing ZnCl 2 and ethylene glycol was adopted as non-aqueous electrolyte for ZIHS, 26 displaying a wide and stable electrochemical potential window up to 1.6 V and moderate ionic conductivity devote to a ZIHS with an energy density of 52.8 Wh kg −1 at a power density of 384.8 W kg −1 . Wang et al 27 constructed ZIHSs based device on the bio-carbon cathode, metallic Zn foil anode and Zn(CF 3 SO 3 ) 2 electrolyte in acetonitrile or in a mixture of dimethoxyethane and 1,3-dioxolane.…”