Crosslinked Polyethyleneimine Gel Polymer Interface to Improve Cycling Stability of RFBs

Abstract

Redox flow batteries are considered a promising technology for grid energy storage. However, capacity decay caused by crossover of active materials is a universal challenge for many flow battery systems, which are based on various chemistries. In this paper, using the vanadium redox flow battery as an example, we demonstrate a new gel polymer interface (GPI) consisting of crosslinked polyethyleneimine with a large amount of amino and carboxylic acid groups introduced between the positive electrode and the membrane. The GPI functions as a key component to prevent vanadium ions from crossing the membrane, thus supporting stable long-term cycling. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were conducted to investigate the effect of GPI on the electrochemical properties of graphitic carbon electrodes (GCFs) and redox reaction of catholyte. X-ray photoelectron spectroscopy (XPS) and 1H nuclear magnetic resonance (NMR) spectra demonstrated that the crosslinked GPI is chemically stable for 100 cycles without dissolution of polymers and swelling in the strong acidic electrolytes. Results from inductively coupled plasma mass spectrometry (ICP-MS), Fourier-transform infrared (FTIR) spectroscopy, and energy-dispersive X-ray (EDX) spectroscopy proved that the GPI is effective in maintaining the concentration of vanadium species in their respective half-cells, resulting in improved cycling stability because of it prevents active species from crossing the membrane and stabilizes the oxidation states of active species.

Chlorpyrifos Release Kinetics from Citric Acid Crosslinked Biopolymeric Nanoparticles: A Sustainable Approach

“…The image revealed the uniform and smooth surface of nano formulation. Results obtained were found comparable to the results obtained by Kulkarni et al [17] and Lim et al [18]. As the chlorpyrifos particles have rod like structure [19] and the rod like particles were found entrapped or embedded inside the polymeric matrix (Fig.…”

A quasi-solid-state self-healing flexible zinc-ion battery using a dual-crosslinked hybrid hydrogel as the electrolyte and Prussian blue analogue as the cathode material

“…S10 †). The abundant amino (-NH2), hydroxyl (-OH), and carbonyl (C=O) groups in the hybrid electrolyte might avoid electrolyte crossover and enhance the wettability among the interface between electrolyte and electrode 32 . These functional groups lead to the formation of hydrogen bonds in the aqueous environment, showing outstanding self-healing performance 33 .…”

“…The abundant amino (–NH 2 ), hydroxyl (–OH), and carbonyl (C O) groups in the hybrid electrolyte might avoid electrolyte crossover and enhance the wettability at the interface between the electrolyte and electrode. 32 These functional groups lead to the formation of hydrogen bonds in an aqueous environment, showing outstanding self-healing performance. 33 When the broken pieces were re-connected, plenty of new hydrogen bonds were regenerated between the functional groups and water molecules which exist on the fractured interfaces.…”

Progress of organic, inorganic redox flow battery and mechanism of electrode reaction

“…Therefore, the electrodes are the main factor limiting the performance of VFB. Graphite felt (GF), carbon felt (CF), carbon cloth (CC), and other carbon-based electrode materials have the advantages of low cost, high stability and conductivity, corrosion resistance, and so on [5,47,48]. Various strategies, including heat treatment, acid activation, chemical etching, and polymer modification, have been successfully used to improve the wettability and activity of electrodes [26,48,49].…”