Spinifex nanocellulose derived hard carbon anodes for high-performance sodium-ion batteries

The selection of an appropriate anode material is a critical factor in dictating the effectiveness of sodium-ion batteries as a cost-effect alternative to lithium-ion batteries. Hard carbon materials sourced from biomass offer the potential for a more sustainable anode material, while also addressing some of the thermodynamic issues associated with using traditional graphite anodes for sodium-ion batteries (NIBs). Herein, we report the preparation of carbon electrode materials from low-cost cellulose nanofibers derived from an Australian native arid grass ‘spinifex’ (Triodia pungens). This nanocellulose derived carbon produced by a fast, low temperature carbonization protocol showed superior performance as an anode for NIBs with a specific capacity (386 mA h g−1 at 20 mA g−1) on par with that of the graphite based anode for lithium-ion batteries, and is one of the highest capacity carbon anodes reported for NIBs. The excellent electrochemical performance is attributed to the large interlayer spacing of the carbon (∼0.39 nm). Superior cycling stability and high rate tolerance (326 mA h g−1 at 50 mA g−1 and 300 mA h g−1 at 100 mA g−1) suggest that hard carbons derived from sustainable precursors are promising for next generation rechargeable batteries.