Graphite felt modified withWO₃,SnO₂,and binaryWO₃/SnO₂‐mixtures as novel positive electrodes for cerium‐based redox flow batteries

Abstract

Cerium-based redox flow batteries (RFBs) such as Zn-Ce and V-Ce have received attention as attractive energy storage systems due to their high opencircuit cell voltages. To date, the most successful Ce-based RFBs have relied on expensive Pt-based positive electrodes. In this study, the use of more economical polyacrylonitrile (PAN)-based graphite felt (GF) containing tungsten oxide (WO 3 ) and/or tin oxide (SnO 2 ) nanocatalysts is examined for its electrochemical activity for the Ce(III)/Ce(IV) redox reaction in a series of half-cell experiments. Cyclic voltammetry is carried out at room temperature in a 0.05 M Ce(III) methanesulfonate +1.0 M methanesulfonic acid (MSA) electrolyte using a custom-made three-electrode cell. Among all modified GFs, those coated with a binary WO 3 -SnO 2 mixture have exhibited superior electrocatalytic activity toward the Ce(III)/Ce(IV) reaction compared to the ones decorated with single oxides WO 3 or SnO 2 . Presumably, this can be ascribed to the involvement of both metal oxides (WO 3 and SnO 2 ) in promoting electrolyte accessibility and improving the hydrophilicity of GF electrodes. SEM images indicate that the combination of WO 3 and SnO 2 promotes a more homogeneous dispersion over the graphite fiber surface and prevents clustering of the oxide particles that is more evident in the case of the single metal oxide catalysts.

The Modification of WO3 for Lithium Batteries with Nickel-Rich Ternary Cathode Materials

“…By comparing the spectra, it was found that all samples exhibited inherent Ni, Co, and Mn characteristic peaks, while the samples added with WO 3 exhibited obvious W element characteristic peaks, indicating that the single-crystal ternary material successfully achieved WO 3 addition. Cyclic and rate performance tests were conducted on each sample in an electrochemical window of 2.8-4.4 V at room temperature [33]. All cycle and rate performance analyses are shown in Figure 8.…”

Review—Flow Batteries from 1879 to 2022 and Beyond

“…The high cost and limited durability of platinum, as well as problems with remixing and rebalancing the electrolytes during cycling, were probably the main reasons for Plurion's eventual liquidation. Although there has been some interest in revising Zn-Ce RFBs recently, 160,161 this technology is considered as a "no-go" by most RFB developers.…”