Upcycling complex ion industrial wastewater to high-performance hybrid anodes for lithium-ion batteries

The flourish of renewable clean energy has stimulated the fast development of advanced electrochemical energy storage technology. Among them, the development of lithium-ion batteries (LIBs) has attracted much attention, but their promotion is limited by the high cost and insufficient resources. Meanwhile, the prosperity of industry leads to the discharge of a large amount of complex-metal-ion-containing industrial wastewater, which not only seriously harms the environment but also causes waste of resources. Here, budget and accessible sodium alginate (SA) extracted from algae is used as a metal trapping agent. Benefiting from the crosslinking mechanism between functional groups of SA and complex multivalent metal ions, it can successfully realize the synchronous capture and recovery of multiple metal ions in industrial wastewater. Through facile annealing treatment and coating process, the captured metal ions from industrial wastewater are converted into high-performance SA-encapsulated metal oxide anode materials with core-shell structure, delivering high specific capacity and exhibiting outstanding cycling stability. This strategy simultaneously realizes environmental protection and waste recovery, achieving the unity of environmental, social and economic benefits.