Chiral bioderived supercapacitor electrodes based on cellulose nanocrystals†

The advancement of high-performance thin-film electrodes for next-generation supercapacitors is often hindered by the high cost and aggregation behavior of two-dimensional nanomaterials such as reduced graphene oxide (rGO). Here, we demonstrate that integrating rGO into a chiral, bio-derived matrix of cellulose nanocrystals (CNCs) via evaporation-induced self-assembly can simultaneously improve electrochemical performance and reduce rGO loading. Specifically, we investigate how CNC chirality directs rGO dispersion and modulates ionic transport pathways through hydrogen bonding and structural templating. The resulting CNC/rGO nanocomposites retain key features of chiral organization and exhibit reduced rGO restacking. The optimized CNC/10 wt% rGO composite achieved a specific capacitance of 209 F g⁻¹ at 20 mV s⁻¹ and 224 F g⁻¹ at 2.0 A g⁻¹, representing a 93% improvement over pure rGO, along with a volumetric energy density of 17.6 W h L⁻¹ at 204 W L⁻¹ and stable performance across a wide power range. This work offers a scalable and sustainable route to engineer nanostructured electrodes, revealing how chirality in bio-based materials can be harnessed to enhance charge storage and ion accessibility.