Production of the C/TiO composite with a high-performance electrochemical property from titanium-rich sludge via in-situ C coating.

Resource recycling from waste-water and sludge is an important part of the 14th Five-Year Plan in China. The emerging titanium-based coagulants have drawn growing attentions due to their strong coagulation capability in water purification and value-added Ti-loaded sludge production. Management and recovery of the high value-added sludge into functional nanomaterials is highly significant for both sludge reduction and environmental remediation. The present study was carried out to investigate the recycle of the coagulated Ti-loaded sludge to produce functional C/TiO composites as the anode materials for lithium-ion batteries (LIBs). It is the first time that the application of the Ti-loaded wastewater sludge derived C/TiO was evaluated for LIBs. The experimental results showed that the carbon coating through in-situ carbonization of the sludge produced the C/TiO composites with a high specific surface area, stable structural integrity, and excellent electrochemical properties that would facilitate Li diffusion in long-term LIBs usage. The C/TiO composites calcinated from the polytitanium sulfate-coagulated sludge at 800°C (N) exhibited the best electrochemical performance during the cycling tests (601 mAh/g at 100 mA/g after 200 cycles). The research work demonstrates the promising prospect of the recycle and value-added utilization of the Ti-loaded sludge in the production of high-performance C/TiO composites for energy storage applications. This study provides a new way for the management and reuse of Ti-loaded waste-sludge.