Towards sustainable electrochemical energy storage: solution-based processing of polyquinone composites

Continuous adoption of renewable energy sources and the proliferation of electric transportation technologies push towards sustainable energy storage solutions. Consequently, a solution-based up-scalable synthesis approach is developed for polymeric quinone composites with graphene. Cellulose nanocrystals play a vital role in achieving greener processing and improving the composite electrochemical energy storage performance. The synthesis method emphasizes using aqueous reaction media, incorporates low-cost and biomass-derived feedstocks, avoids critical or scarce materials, and maintains temperatures below 200 degrees C. Stable aqueous graphene dispersions were obtained by hydrothermal reduction of electrochemically exfoliated graphene oxide in the presence of cellulose nanocrystals. Dispersions served as a reaction medium for quinone cationic polymerization, leading to core-shell type structures of polymer-covered mono-to-few layer graphene, thanks to the nanosheet restacking prevention effect provided by cellulose nanocrystal dispersions. A sample consisting of 5 wt% cellulose nanocrystals and 5 wt% graphene achieved storage metrics of 720.5 F g(-1) and 129.6 mA h g(-1) at 1 A g(-1), retaining over 70% of the performance after 1000 charge/discharge cycles.

Automated summary

A green and scalable synthesis method for polymeric quinone composites with graphene has been developed, utilizing cellulose nanocrystals to improve the electrochemical energy storage performance. This method avoids critical materials, uses low-cost feedstocks, and achieves stable aqueous graphene dispersions. The composite material showed high storage metrics and retained over 70% performance after 1000 charge/discharge cycles.