Owing to the steep increase in the use of secondary batteries, there has been a drastic rise in the demand for lithium. Currently, lithium production is majorly carried out via evaporation and precipitation method using brine lake waters; however, this process requires long period (several months) for the production of lithium and can only be applied to limited water sources that contains low amount of certain ions. In addition, there are environmental issues regarding the evaporation and precipitation method, and thus development of highly efficient and environmentally benign lithium recovery process is an urgent task. This is also important in the economical viewpoint, given that the lithium-based industry and market are always under rapid changes. Recently, innovative approaches for lithium production have been performed by using electrochemical lithium recovery systems comprising a lithium ion-selective electrode (e.g. LiMn2O4 or LiFePO4) and a counter electrode to capture anions (typically silver electrode to capture chloride ions). This system manifested high selectivity for lithium and low energy consumption, implying its feasibility in practical and industrial applications. Nonetheless, high cost and poor long-term stability of silver electrode is impeding the wide usage of this lithium recovery system. In order to resolve the shortcomings of the silver electrode, there have been several approaches introducing other electrode materials including activated carbon, polypyrrole and water splitting electrodes. However, the proposed electrochemical systems also suffered from low capacity and high energy consumption. We herein suggest new electrode designs for Faradaic and non-Faradaic capture of anions, by modifying the silver-based electrode and using a carbonaceous material with a large surface area, respectively. By various physicochemical characterizations and electrochemical evaluations, high performance and durability of the electrodes were demonstrated. Moreover, we prepared a system that enables lithium recovery and decomposition of organic pollutant simultaneously, by which we could extend the usage of this electrode to an industrial wastewater and confirm the wide applicability of the electrochemical system for versatile situations.

Faradaic and non-Faradaic electrode designs for robust electrochemical lithium recovery from brine and wastewater

256th National Meeting (2018)

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