Greenly growing carbon nanotubes on graphene for high-performance lithium-sulfur batteries

The expanding energy storage market in response to global decarbonization goals generates countless waste, causing severe environmental issues. To address this dilemma, end-of-life batteries must be upcycled for a second life. Here we report an all-green strategy for growing carbon nanotubes (CNTs) on graphene. The graphene was upcycled from end-of-life lithium-ion batteries and the CNTs were then grown directly on the graphene by pyrolyzing biomass as the carbon source and yeast as the catalyst. When being used in a lithium-sulfur battery cathode, the graphene provided a highly conductive network while the CNTs enabled high sulfur loading and volume buffering, rendering the battery with high capacity, high stability, and long lifespan. The CNT/graphene constructed battery exhibited longevity of over 1500 cycles with a capacity fading rate of 0.042% per cycle and a steady Coulombic efficiency of over 97%. The all-green CNT/graphene hybrids present new pathways to upcycling batteries to second life.(c) 2023 Elsevier Ltd. All rights reserved.