A Low-Crossover and Fast-Kinetics Thiolate Negolyte for Aqueous Redox Flow Batteries

Abstract

Aqueous redox flow batteries (ARFBs) are a promising technology for large-scale energy storage. Developing high-capacity and long-cycle negolyte materials is one of major challenges for practical ARFBs. Inorganic polysulfide is promising for ARFBs owing to its low cost and high solubility. However, it suffers from severe crossover resulting in low coulombic efficiency and limited lifespan. Organosulfides are more resistant to crossover than polysulfides owing to their bulky structures, but they suffer from slow reaction kinetics. Herein, we report a thiolate negolyte prepared by an exchange reaction between a polysulfide and an organosulfide, preserving low crossover rate of the organosulfide and high reaction kinetics of the polysulfide. The thiolate denoted as 2-hydroxyethyl disulfide+potassium polysulfide (HEDS+K2S2) shows reduced crossover rate than K2S2, faster reaction kinetics than HEDS, and longer lifespan than both HEDS and K2S2. The 1.5 M HEDS+1.5 M K2S2 static cell demonstrated 96 Ah L-1negolyte over 100 and 200 cycles with a high coulombic efficiency of 99.2% and 99.6% at 15 and 25 mA cm-2, respectively. The 0.5 M HEDS+0.5 M K2S2 flow cell delivered a stable and high capacity of 30.7 Ah L-1negolyte over 400 cycles (691 h) at 20 mA cm-2. This study presents an effective strategy to enable low-crossover and fast-kinetics sulfur-based negolytes for advanced ARFBs.

Ultrathin PtRu Nanowires as Efficient and Stable Electrocatalyst for Liquid Fuel Oxidation Reactions

“…The ultrathin PtRu NWs were synthesized via a colloidal chemistry approach by using platinum acetylacetonate (Pt(acac) 2 ) and ruthenium acetylacetonate (Ru(acac) 3 ) as the metal precursors, tungsten hexacarbonyl (W(CO) 6 ) and (1-hexadecyl) cetyltrimethylammonium bromide (CTAB) as the structure-directing agents, and oleylamine as the solvent. The mixture was then heated to 220 °C for 5 h in an oil bath.…”

“…The development of environment-friendly and sustainable energy technologies is critical for the comprehensive transformation of energy structure from fossil fuels to renewable energy sources in the future [1][2][3][4][5][6][7][8]. Direct liquid fuel cells (DLFCs) technology provides a promising strategy to convert chemical energy into electric power [9].…”

Cathode materials for halide-based aqueous redox flow batteries: recent progress and future perspectives

“…Relatively, Wang et al reported a thiolate negolyte prepared by an exchange reaction between a polysulfide and an organosulfide, preserving the low crossover rate of the organosulfide and high reaction kinetics of the polysulfide. 89 Various PIRFBs of different positive and negative electrodes at a current density of 20 mA cm −2 under relatively similar operating conditions are summarized in Table 2. Fig.…”

Two-dimensional materials for aqueous zinc-ion batteries

“…Aqueous Zn-ion batteries (ZIBs) have been considered as one of the promising energy storage systems for large-scale energy storage because of their high safety, low cost and environmental friendliness [1][2][3][4][5][6]. The development of aqueous ZIBs mainly focuses on the design of electrodes, optimization of electrolytes, and improvement of device configurations [7][8][9][10].…”