Progress and challenges in using sustainable carbon anodes in rechargeable metal-ion batteries

Abstract Rechargeable lithium-ion batteries (LIBs) are one of the most promising alternatives to effectively bypass fossil fuels. However, long-term energy application of LIBs could be restricted in the future due to the increased production cost of LIB arising from the shortage and inaccessibility of Li in the Earth's crust. Na or K have been considered as substitutes for Li but in spite of their natural abundance, they suffer from low gravimetric/volumetric energy density. An alternative to increase the efficiency of sodium-ion battery (SIBs) and potassium-ion battery (KIBs) is to focus on finding the high‐performing negative electrode, the anode. The large volume changes of alloying and conversion type anodes for KIBs and SIBs make hard carbons to a better option on this regard than usual graphitic carbons, but a key obstacle is the reliance on unsustainable sources. Thus, biomass-derived carbon could offer a promising alternative, and it has indeed been in the focus of much recent work. This review highlights the recent advances in using carbon extracted from various biomass sources in rechargeable Li-, Na-, and K-ion batteries. Maximizing the energy and power densities as well as the lifetime of carbon anodes require an exploration of the right balance between carbon structures, pore morphology, chemical composition and alkali metal-ion storage. Thus, in this review, first, we take stock of key challenges and opportunities to extract carbon from various plants structural components and identify the extracted carbon structure compared to graphite-like structure. Then, we provide an overview on morphological and structural modification of the extracted carbons. Finally, we show how the physicochemical properties, structural alignment and morphological variation of the biomass-derived carbon can affect the storage mechanism and electrochemical performance. The extensive overview of this topic provided here is expected to stimulate further work on environmentally friendly battery design and towards the optimization of the battery performance. Electrode materials in alkali-metal-ion batteries that are based on biomass-derived carbon may allow not only a technical breakthrough, but also an ethically and socially acceptable product.