Electrochemical properties of biomass-derived carbon and its composite along with Na2Ti3O7 as potential high-performance anodes for Na-ion and Li-ion batteries

Abstract Porous carbon has been synthesized from the seeds of Tamarindus indica plants at a moderately low temperature. The charge-storage property of the as-prepared carbon anode has been tested at 0.2 A g‒1 against sodium metal in half-cell and Na3V2(PO4)3 (NVP) in sodium-ion full-cell configurations and it exhibits a specific capacity of ∼162 mAh g−1 after 200 cycles and ∼164 mAh g−1 after 50 cycles respectively. Further, the composite of biocarbon with Na2Ti3O7 (NTO) has been synthesized, which shows the NTO phase transformation from monoclinic to predominantly triclinic phase during the composite preparation. The composite anode against sodium metal delivers a reversible specific capacity of 135 mAh g−1 at 0.2 A g‒1 after 250 cycles. The excellent electrochemical performance of the composite is attributed to its superior electronic conductivity, better structural stability and presence of the triclinic phase. This is supported by the first-principles density functional theory calculations, ex-situ X-ray photoelectron spectroscopy (XPS) studies and the repeated charge/discharge cycling performances. Furthermore, the performance of biocarbon anode in lithium half-cell configuration and lithium-ion full-cell configuration against LiNi0.8Co0.15Al0.05O2 (NCA) cathode has been tested and the latter shows a reversible specific capacity of ∼393 mAh g‒1 after 200 cycles at 0.2 A g‒1.