The Greencap project contributed to the development of new SCs with energy densities comparable to batteries by synthesizing five types of CRM-free MXenes, which enhanced performance. The creation of ionogel-type electrodes using cost-effective, water-soluble binders and IL-based electrolytes ensured optimal electrolyte wetting and reduced costs. Improved methods for producing FLG with sustainable water-based media and surfactants, along with the synthesis of protonated ILs, further boosted the SCs' efficiency and longevity. These advancements led to SCs that recharge much faster than current batteries, maintain consistent performance over time, have longer lifespans, and exhibit a low environmental impact. We optimized the production processes on the entire value chain, developing prototypes that demonstrate the feasibility and efficiency of these advanced energy storage systems, using CRM-free materials. The active presence of the advisory board provided specifications tailored to specific market needs. The active collaboration of the advisory board members ensured that the solutions developed are not only innovative but also well-aligned with industry requirements and expectations. Based on a screening of commercially available SC technologies,the consortium created device performance benchmarks with a key indicator set, including capacitance/capacity, working voltage, lifetime, cycle life, working temperature, and cost.
Greencap targeted the adoption of industrially compatible methodologies to produce few-layer graphene and MXene using sustainable components and CRM-free precursors. Thank to the complete value chain from material to cell producers we validated all the steps in industrial environments, including large-scale material production, aqueous-based slurry formulation for roll-to-roll fabrication of high mass loading electrodes and development of multilayer industrial cylindrical cells. The key challenges tackled by Greencap were the industrialization and commercial potential of sustainable 2D Materials and ILs for SCs. The production of graphene materials from synthetic graphite/waste source via sustainable processes. The production of CRM-free MXenes via fluoride-free etching method. The upscaling, at the tons scale, of the production of both 2D Materials and ionic liquid-based electrolytes. The acquisition of fundamental and practical understanding of the electrochemistry at the 2D Materials/IL interfaces, coupled with new insight into interface modelling. The functionalization of 2D Materials with redox active group or dopants introduced Faradaic storage mechanisms. Advanced in-situ and operando material and device characterizations was pivotal in understanding capacitive and Faradaic processes. A rational and controlled functionalization/hybridization of 2D Materials has been reached together with the engineered electrode density to guarantee high electrolyte accessibility to their surface area. We developed aqueous-based slurry formulations with a reduced amount of binder and conductive additive. We optimized the electrode thickness and mass loading, achievieng high gravimetric (>200 F/g) and volumetric capacitances (>150 F/cm3) with commercial-like mass loadings (4-6 mg/cm2) at pouch cell level. We desigend and realized a CRM-free cylindrical D60 prototype SCs satisfying industrial requirements at 2.85 V with their own management system, achieved battery-like energy density (>20 Wh/kg, >14 Wh/L), retaining all the peculiar characteristics of EDLCs.
