Improving the electrochemical performance of α-MoO_(3) electrode using aluminium trifluoromethanesulfonate water-in-salt electrolyte  

作　　者：Ayman E.Elkholy Timothy T.Duignan Ruth Knibbe Xiu Song Zhao 

机构地区：[1]School of Chemical Engineering,The University of Queensland,St Lucia Campus,Brisbane 4072,Australia [2]School of Mechanical and Mining Engineering,The University of Queensland,St Lucia Campus,Brisbane 4072,Australia

出　　处：《Journal of Energy Chemistry》2023年第3期123-134,I0004,共13页能源化学（英文版）

基　　金：supported by the Australian Research Council under the ARC Laureate Fellowship program(FL170100101)。

摘　　要：Orthorhombic molybdenum trioxide(α-MoO_(3)) electrode material experiences severe capacity fading and poor cycling stability in aqueous electrolytes.We investigated the charge-storage performance of α-MoO_(3) electrode in aluminium trifluoromethanesulfonate(Al(OTf)_(3))-based salt-in-water electrolyte(SiWE) and water-in-salt electrolyte(WiSE).It was found that α-MoO_(3) electrode exhibits significantly different cycling stabilities in both electrolytes with capacity retentions of 8% using the former and87% using the latter.This is because α-MoO_(3) electrode maintains its crystal structure upon cycling in WiSE,but experiences substantial structural collapses and partial dissolution upon cycling in SiWE.This behaviour was inferred from both operando electrogravimetry and ex situ analyses.Research results suggest that the predominant charge-storage mechanism in a-MoO_(3) electrode using WiSE is the intercalation of protons produced from electrolyte hydrolysis with some contribution from surface pseudocapacitance enabled by Al3+ions.A two-volt full cell fabricated from α-MoO_(3) electrode as anode and copper hexacyanoferrate(CuHCF) electrode as cathode using WiSE delivers volumetric and gravimetric energies of 10.4 Wh/L and 26.5 Wh/kg,respectively,with 78% capacity retention after 2500 cycles.This study provides an insightful understanding of the electrochemical performance of α-MoO_(3) electrode in Al(OTf)_(3)-based electrolytes.

关 键 词：Molybdenum oxide Aqueous electrolyte Water-in-salt electrolyte Aqueous batteries PSEUDOCAPACITANCE 

分 类 号：TM912[电气工程—电力电子与电力传动] O646.54[理学—物理化学]