Simple-Synthesized Sulfonated Ferrocene Ammonium for Aqueous Redox Flow Batteries

Abstract

To achieve sustainable development, the development and utilization of redox-active organic species in aqueous redox flow batteries provide broad prospects for large-scale and sustainable energy storage. Herein, we report a sulfonated ferrocene derivative, ferrocene ammonium sulfonate, that is stable and easy to synthesize. We applied it as a catholyte in zinc hybrid flow batteries. Through the adjustment of the electrolyte, the battery showed high capacity retention and efficiency. When the current density was 20 mA/cm2 and 0.5 M NaCl + 0.5 M NH4Cl solution was used as the supporting electrolyte, the capacity retention reached 92.55% after 100 consecutive charge/discharge cycles. In addition, the coulombic efficiency, energy efficiency, and voltage efficiency stayed at 98.33, 83.19, and 84.60%, respectively. This battery design puts forward an idea for developing low-cost materials and improving capacity retention.

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

“…11,12 RFB enables the megawatt level capability to cooperate with electricity grids by simply changing the volume of the reservoir or the concentration of adjusted storage capacity. 13,14…”

“…11,12 RFB enables the megawatt level capability to cooperate with electricity grids by simply changing the volume of the reservoir or the concentration of adjusted storage capacity. 13,14 Relative to organic RFB systems with flammable organic solvents, the ARFB systems as a typical RFB with aqueous electrolytes exhibit competitive advantages in LSESA, with respect to Li-ion ESB that show lower electrolyte resistance, higher power density, lower cost, and better environmental friendliness. 15,16 The EAS is usually highly soluble to achieve high energy densities and possesses highly reversible kinetics to minimizing activation over-potential losses in both the oxidation and reduction reactions.…”

Ferrocene to functionalized ferrocene: a versatile redox-active electrolyte for high-performance aqueous and non-aqueous organic redox flow batteries

“…Iron containing ferrocene is less problematic to the market as its easy availability, safe to handle, less expensive and less toxic in nature. 10,11 Additionally, the theoretical capacity of ferrocene is 145 mA h g −1 . 12 Still, the problems persist, as ferrocene is hydrophobic in nature and does not dissolve in most of organic solvents.…”

A Neutral‐pH Aqueous Redox Flow Battery Based on Sustainable Organic Electrolytes

“…For this reason, the ferrocene/ferrocenium ion redox couple has found application as model chemistry for non‐aqueous redox flow battery research [39–42] . Previous reports dealt with modifying hydrophobic Fc with hydrophilic moieties, resulting in an increased solubility in an aqueous solution [43–49] . Z. Zhao et al [50] .…”

“…[39][40][41][42] Previous reports dealt with modifying hydrophobic Fc with hydrophilic moieties, resulting in an increased solubility in an aqueous solution. [43][44][45][46][47][48][49] Z. Zhao et al [50] used 1,1'bis(sulfonate)-ferrocene dianion disodium salt pared with the anthraquinone-2,7-disulfonic acid disodium salt; on the other hand, ferrocene decomposed under the acidic conditions used to stabilize the anthraquinone. [42] Considering our expertise in synthesis and applications of electro-active molecules, in particular metallocenes, [51][52][53][54] we synthesized in this work the 1,1'-bis(sulfonate)-ferrocene dianion disodium salt (DSÀ Fc) and two viologen-derivatives, as catholyte and anolyte, respectively, to produce a sustainable neutral-pH AORFB.…”