Nickel hexacyanoferrate as suitable alternative to Ag for electrochemical lithium recovery.

Currently, Li is mainly produced through evaporation of Li-rich brines obtained from South American countries such as Bolivia, Chile, and Argentina. The most commonly used process, the lime-soda evaporation, requires a long time and several purification steps, which produces a considerable amount of chemical waste. Various electrochemical methods have been proposed as alternatives, but they use expensive metals such as Ag or Pt, thus rendering these methods economically unacceptable. In this work, we present KNiFe(CN)6 , an abundant and environmentally friendly material, as alternative to these expensive components. The Prussian blue derivate has a higher affinity toward cations (Na(+) or K(+) ) than for Li(+) . Additionally, the use of KNiFe(CN)6 permits the utilization of seawater or brine water as recovery solution, thus reducing the consumption of fresh water, which is typically a scarce element in Li production sites.