Deep eutectic solvents assisted biomass pre-treatment to derive sustainable anode materials for lithium-ion batteries

Biomass such as agricultural waste is an attractive and sustainable source to produce electrode materials for energy storage systems. The pre-treatment of biomass is a key process that determines the quality of resulting material and consequently defines the performance of the device. In common practice, aggressive and toxic chemicals such as inorganic acids and alkaline solvents have extensively been used, which threatens environmental and human health. Herein, we have presented deep eutectic solvents (DES)-based green, inexpensive and effective solvents for the pre-treatment of rice-husk (RH) biomass. The results demonstrate that DES efficiently and selectively remove the inorganic impurities from RH without affecting their organic content. Later, the DES pre-treated RH were transformed into silicon/carbon (Si/C) nanocomposite using single step pyrolysis method and employed as anode materials for lithium-ion battery (LIB). It was revealed that DES significantly affects the structural and morphological properties of resulting Si/C materials. Benefiting from the unique hierarchical characteristics of Si/C nanocomposites, all the samples delivered excellent electrochemical properties with maximum specific capacity of 372.5 mAh/g and pro-longed cycling stability. Thus, the present investigation provides green and cost-effective strategy for pre-treatment of rice-husk, which can be further extended to various biomass.