Electrochemical Production of Exfoliated Graphene: Scale-up and Applications
Authors: Roberts Edward , Singh Ashutosh Kumar , Sadri Rad , Liu Yiran , Cao Yifan 
Published: December 2024

We have previously reported on the production of high quality graphene nanoplatelets by anodic electrochemical intercalation / exfoliation of graphite in simple aqueous salt solutions [1-3]. The process is attractive as it operates under ambient conditions, achieves a relatively high yield, and the graphene product does not require thermal or chemical reduction. In addition, heteroatom doping and surface functionalization ensure effective dispersion (enabling simple processing) and excellent performance for a range of applications, including supercapacitors [4,5], redox flow batteries [6], CO2 capture [7], and water treatment [8]. A key step for widespread implementation of electrochemically exfoliated graphene in these applications is the scale up of the process for cost effective production. In this study, a range of scale-up challenges have been evaluated, including the applied current density, temperature control, electrode dimensions and thickness, current connections, electrolyte volume and flow conditions, water purity, electrolyte recycling. The results demonstrate the scalability of the process, but also highlight critical issues that must be considered to enable successful scale-up. In particular, selection of the electrode dimensions must consider the potential and current distribution in the graphite working electrode. Temperature control is also important, since significant joule heating of the electrolyte occurs as the process is scaled up. A material and energy balance reveals that electrolyte management / recycling will be important for reducing waste. Economic analysis suggests that more than half of the cost of production is associated with the graphite foil raw material, and significantly lower cost may be achieved by changing to the process to a packed bed graphite flake electrode.

[1] Sharif et al. Synthesis of a high-temperature stable electrochemically exfoliated graphene. Carbon 157 (2020) 681-692

[2] Momodu et al. Mixed-acid intercalation for synthesis of a high conductivity electrochemically exfoliated graphene. Carbon 171 (2021) 130-141

[3] Roberts and Singh, Electrochemical graphene exfoliation with hydroxide intercalation. US Patent Application 17174552 (2021)

[4] Cao et al., A Flexible Nanocomposite Film of Electrochemically Exfoliated Graphene @ Ti3CNTx for Supercapacitors with high Volumetric Capacitance. ACS Materials Letters 6 (2024) 2360-2368

[5] Momodu et al. Hybrid energy storage using nitrogen-doped graphene and layered-MXene (Ti3C2) for stable high-rate supercapacitors. Electrochimica Acta 388 (2021) 138664

[6] Pahlevaninezhad et al. Exfoliated Graphene Composite Membrane for the All-Vanadium Redox Flow Battery. ACS Applied Energy Materials 6 (2024), 6505-6517

[7] Pal et al. Sustainable CO 2 adsorbent via amine–phosphate coupling of glycated chitosan and electrochemically exfoliated graphene Journal of Materials Chemistry A 12 (2024) 10216-10228

[8] Abuhatab et al. Electrochemical regeneration of highly stable and sustainable cellulose/graphene adsorbent saturated with dissolved organic dye. Langmuir 40 (2024), 3606-3616