Thermodynamic Investigation of Electrolytes of the Vanadium Redox Flow Battery (II): A Study on Low-Temperature Heat Capacities and Thermodynam Properties of VOSO4 · 2.63H2O(s)

摘要

The low-temperature heat capacities of VOSO4 ·2.63H2O(s) which is a key component in the electrolyte of the vanadium redox flow battery were measured by adiabatic calorimetry in the temperature range of (78 to 388) K, and the experimental values of the molar heat capacities in the temperature regions of (78 to 372) K were fitted to a polynomial equation. The polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the compound relative to the standard reference temperature of 298.15 K were calculated at intervals of 5 K. Additionally, a dehydration process occurred in the temperature range of (372 to 382) K, and the peak temperature, T_(de) = (378.895 ± 0.309) K, molar enthalpy of dehydration, Δ_(de)H_m = (116.446 ± 0.148) kJ·mol~(-1), and molar entropy of dehydration, Δ_(DE)S_m = (307.329 ± 0.141) J·K~(-1)·mol~(-1), were determined in terms of the heat capacity curve.