Understanding Charge Storage Mechanisms in Flexible Nanocellulose/Graphite Battery Electrodes

The development of inherently flexible battery electrodes remains a key challenge for modern wearable electronics. Despite the advancement of flexible Lithium-ion (Li⁺) batteries, achieving full adaptability requires redesigning individual battery components. Conventional graphite electrodes are used in Li⁺ batteries but remain rigid and brittle, limiting applications in flexible energy storage. Here, this limitation is addressed by integrating nanocellulose (NCF), a nanoscale biopolymer, with graphite (G), to yield an intrinsically flexible electrode platform. Five NCF/G battery electrode compositions with increasing NCF content (40–70 wt%) are fabricated via a straightforward aqueous route and are evaluated in Li⁺ half cells. Beyond serving as a flexible substrate enduring 180° bending deformation, NCF is shown to actively enhance ion transport for a 60 wt% NCF optimal content. Electrode nanoarchitecture further improves electrochemical characteristics, by implementing electrospun NCF. Molecular-level insights reveal proximity of Li⁺ and NCF surface groups suggesting Li⁺ diffusion through nanochannels. A perspective on the material-driven reshaping of flexible NCF/G battery electrodes is provided, by investigating the contribution of NCF to charge storage mechanisms and to mechanical resilience. This study contributes to the development of battery electrodes that can be tailored to energy storage devices for emerging flexible electronics applications, and towards battery market diversification.