Thermo-osmosis-Coupled Thermally Regenerative Electrochemical Cycle for Efficient Lithium Extraction

Ziwen Yuan; Yanxi Yu; Li Wei; Cheng Wang; Xia Zhong; Xiao Sui; Zixun Yu; Dong Suk Han; Hokyong Shon; Yuan Chen

doi:10.1021/acsami.0c20464

Thermo-osmosis-Coupled Thermally Regenerative Electrochemical Cycle for Efficient Lithium Extraction

ACS Appl Mater Interfaces. 2021 Feb 10;13(5):6276-6285. doi: 10.1021/acsami.0c20464. Epub 2021 Jan 26.

Authors

Ziwen Yuan¹, Yanxi Yu¹, Li Wei¹, Cheng Wang¹, Xia Zhong¹, Xiao Sui¹, Zixun Yu¹, Dong Suk Han², Hokyong Shon³, Yuan Chen¹

Affiliations

¹ School of Chemical and Biomolecular Engineering, The University of Sydney, Camperdown, NSW 2006, Australia.
² Center for Advanced Materials, Qatar University, Doha 24106, Qatar.
³ Center for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.

PMID: 33497188
DOI: 10.1021/acsami.0c20464

Abstract

Lithium (Li) production based on the soda evaporation process is time-consuming and unsustainable. The emerging electrochemical Li extraction is time-efficient but requires high-concentration Li sources and significant electrical energy input. Here, we demonstrate a fast, energy-saving, and environment-friendly Li production process by coupling a thermally regenerative electrochemical cycle (TREC) using lithium manganese oxide (LMO) and nickel hexacyanoferrate (NiHCF) electrodes with poly(vinylidene fluoride) membrane-based thermo-osmosis (denoted as TO-TREC). The characterization of LMO and NiHCF electrodes confirmed that the relatively high temperature of TO-TREC has negligible adverse effects on the ion intercalation in LMO and NiHCF electrodes. The LMO/NiHCF pair has a positive temperature coefficient of 0.843 mV K^-1. In the TO-TREC process, Li ions are selectively extracted from a Li-containing brine warmed by low-grade heat and then released into a room-temperature recovery solution such as LiCl with a production rate of 50-60 mmol Li⁺ m^-2 h^-1. Li source solutions are concentrated by thermo-osmosis simultaneously, making it possible to utilize previously unusable Li-containing sources, such as concentrated brines from desalination plants and industrial effluents. Besides, the TREC harvests thermal energy from the heated brine, saving >20% of electrical energy compared to conventional electrochemical methods. The new process shows the potential to meet the growing global Li demands for many applications.

Keywords: lithium extraction; lithium manganese oxide; nickel hexacyanoferrate; thermal energy harvesting; thermally regenerative electrochemical cycle; thermo-osmosis.