Bio-inspired carbon electrodes for metal-ion batteries

Carbon has been widely used as an electrode material in commercial metal-ion batteries (MIBs) because of its desirable electrical, mechanical, and physical properties. Still, traditional carbon electrodes suffer from limited mechanical stability and electrochemical performance in MIBs. Drawing inspiration from biological species, the carbon allotropes, such as fullerenes, carbon nanotubes, and graphene, can be engineered into mechanically robust, highly conductive frameworks with enhanced ion storage and transport capabilities for MIBs. Here, we present an assortment of bio-inspired carbon electrodes that have enhanced the cycling stability, capacity retention, and overall performance of MIBs. In addition, mimicking the structure and functionality of biological systems has led to the development of flexible MIBs whose performance does not degrade even when stretched, bent, or twisted. Finite element analysis (FEA) is a useful guide in identifying such bio-inspired carbon frameworks because it can simulate and analyze potential failure scenarios, such as stress build-up or structural collapse in MIBs. This review highlights through several examples that there is much scope for improving carbon-based electrode materials through bio-inspired designs for practical high-performance MIBs.