Abstract
Supplies of phosphorus are strongly dependent on imports from China and Morocco. Therefore, development of recycling techniques for phosphorus from industrial waste materials is an important objective for future resource security and supply stability. This study investigated the possibility of recycling phosphorus from waste chemical conversion treatment sludge to produce positive electrodes of lithium-ion secondary batteries. Lithium iron phosphate (LiFePO4) was synthesized using phosphorus and iron contents of waste sludge. The crystal structure and electrode properties of the synthesized LiFePO4 were evaluated. Results show that LiFePO4, which is rechargeable, was synthesized from waste sludge. The positive electrode produced from synthesized LiFePO4 exhibited excellent cyclic performance, although the charge-discharge capacity decreased concomitantly with increasing amounts of sludge. The positive electrode containing 25 % waste sludge as a source of phosphate retained more than 140 mAh g−1 of discharge capacity, which is comparable to commercially used batteries. Results of this work demonstrate the possibility of recycling waste chemical conversion treatment sludge to produce positive electrode materials for lithium-ion secondary batteries.
