H2TiO3 Composite Nanofibers for Lithium Recovery from Spent Lithium-Ion Secondary Batteries

Abstract

Lithium recovery attempts from spent lithium-ion batteries (LIBs) often employed complex methods utilizing toxic chemicals. In this study, a relatively facile and environmentally benign lithium recovery process was developed using H2TiO3 (HTO) as a highly selective lithium-ion adsorbent. This lithium ion sieve (LIS) has a chemically stable structure and remarkably higher theoretical Li+ capacity (126.47 mg/g) than manganese-based LIS. The low titanium dissolution of HTO upon acid pickling makes it an ideal LIS for lithium recovery. However, in its powder form, HTO application in actual systems is limited due to difficulty in its handling. The HTO particles must be incorporated in a suitable support for its feasible utilization. Herein, electrospun nanofibers with unique dimensional properties were utilized to serve as three-dimensional frameworks for HTO. Different types of polymeric (PAN, PSf, PVC, and PVDF) nanofibers with varied HTO loading were prepared by electrospinning method. The composite nanofibers were characterized by SEM, UTM mechanical test and applied for lithium adsorption. It was determined that PAN composite nanofibers with 100 wt.% HTO loading showed the highest adsorption capacity (31.4 mg g-1) and superior mechanical property. It retained up to 93.6% of the adsorption capacity of the pure H2TiO3 powder (33.6 mg g-1). The PAN-HTO nanofiber was then employed to recover Li+ from spent LIBs. The spent batteries were dismantled and sonicated in deionized water to elute Li+ from the waste. The resulting solution was then filtered through the PAN-HTO nanofiber membrane to capture the Li+. The captured Li+ were easily retrieved by mild acid treatment of the spent PAN-HTO nanofiber, which was also regenerated for reuse. Overall, the results of the study showed the feasibility of using PAN-HTO nanofiber for continuous and efficient recovery of lithium ions from spent LIBs. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2009-0093816) and Ministry of Science, ICT and future Planning (2015R1A2A1A15055407).