Exploring spent biomass-derived adsorbents as anodes for lithium ion batteries

Abstract

Hydrochar produced from hydrothermal liquefaction of wastewater-treatment algae has been used as an adsorbent to remove lead(II) from the contaminated water body. The lead-adsorbed hydrochar, that is, a spent adsorbent, is recycled as a carbonaceous anode material prepared for lithium ion batteries. A one-step alkali treatment effectively enhances the electrochemical performance of the adsorbent. After lead adsorption, the spent adsorbent shows high reversible capacity (358 mA h g−1 at 0.1 A g−1 after 100 cycles) and rate capability (383, 312, 261, 214, 175, and 135 mA h g−1 at 0.1, 0.2, 0.4, 0.8, 1.6, and 3.2 A g−1, respectively) as a high-performance carbonaceous anode material. Our work presents a promising strategy to reutilize the spent adsorbent generated from wastewater treatment process as a low-cost and green anode material. Such a waste-to-wealth application could effectively reduce the environmental burden, as well as providing a viable option for transforming heavy metal–enriched carbon waste into high–value-added material, which meanwhile helps to fulfill a growing demand on the electrochemical energy storage devices.