Sustainable Fabrication of Carbon Electrodes via Organic-Solvent-Free Aqueous Spray Coating for Energy-Efficient Redox-Mediated Electrodialysis.

Redox-mediated electrodialysis (redox-ED) has emerged as a transformative desalination technology, significantly reducing operational cell voltage by replacing conventional water splitting with reversible redox reactions. However, the widespread reliance on organic-based binders and toxic solvents during electrode fabrication remains a critical bottleneck for its sustainable deployment. This study reports a solvent-free aqueous spray coating strategy for the fabrication of eco-friendly carbon electrodes using a synergistic green binder system composed of styrene-butadiene latex (SBL) and carboxymethyl cellulose (CMC). The influence of SBL content (2-5 g) on the microstructural evolution and electrochemical kinetics of the electrode was systematically investigated. The electrode with an optimized binder ratio of 4 g SBL and 0.3 g CMC exhibited a superior salt removal rate of 764.1 mmol m-2 h-1, charge efficiency of 98.2%, and low energy consumption of 117.8 kJ mol-1, representing a 2-fold enhancement compared with the 2 g SBL and 0.3 g CMC electrode configuration. Mechanistically, this superior performance was attributed to the optimized SBL/CMC ratio, which promotes an ideal trade-off between structural integrity and ionic accessibility. Notably, the balanced binder distribution led to a homogeneous carbon particle network, yielding an exceptional specific surface area (1780.7 m2 g-1) and a high specific capacity (0.130 mAh g-1). Furthermore, this optimized interfacial architecture significantly minimized the charge transfer resistance (Rct = 0.81 Ω), accelerating the redox-shuttle kinetics at the electrode-electrolyte interface. These findings demonstrate that this aqueous-processed, scalable fabrication method not only mitigates environmental burden but also provides a pathway for the industrial-scale implementation of sustainable redox-ED systems.