Sodium-ion battery anodes from carbon depositions

Significant interest is directed towards converting CO2 to high-value feedstock chemicals. Here, the performance of carbon deposited from carbonate fluxes under CO2 environments are reported for direct use as anodes in sodium-ion batteries. The generated carbon is found to be amorphous hard carbon, evidenced by X-ray diffraction (XRD) data and ID/IG ratios of the D- and G- bands of graphite in Raman spectroscopy. Furthermore, the role of washing and removing the deposit is evaluated for the carbon generated and the subsequent electrochemical performance. The best performing samples were grown on a copper substrate, which delivered initial reversible capacities of 209 ± 23 mAh/g mAh/g on the 5th cycle at a rate of 10 mA/g, and feature a capacity retention of 86.6 ± 1.8 % after 50 cycles. The value in this approach to generate carbons lies in the fact that these fluxes are designed to be similar to that used for molten salts in solar thermal plants and, if coupled appropriately to CO2 sources, they can be used to convert CO2 into carbons. A model system is proposed on how this can be achieved to possibly produce a carbon negative anode for sodium-ion batteries, with potential for an overall carbon negative sodium-ion battery.