A new zinc-ion battery based on copper hexacyanoferrate and zinc foil in a 20 mM solution of zinc sulfate, which is a nontoxic and noncorrosive electrolyte, at pH 6 is reported. The voltage of this novel battery system is as high as 1.73 V. The system shows cyclability, rate capability, and specific energy values near to those of lithium-ion organic batteries based on Li4 Ti5 O12 and LiFePO4 at 10 C. The effects of Zn(2+) intercalation and H2 evolution on the performance of the battery are discussed in detail. In particular, it has been observed that hydrogen evolution can cause a shift in pH near the surface of the zinc electrode, and favor the stabilization of zinc oxide, which decreases the performance of the battery. This mechanism is hindered when the surface of zinc becomes rougher.

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Due to the ubiquitous presence of lithium‐ion batteries in portable applications, and their implementation in the transportation and large‐scale energy sectors, the future cost and availability of lithium is currently under debate. Lithium demand is expected to grow in the near future, up to 900 ktons per year in 2025. Lithium utilization would depend on a strong increase in production. However, the currently most extended lithium extraction method, the lime‐soda evaporation process, requires a period of time in the range of 1–2 years and depends on weather conditions. The actual global production of lithium by this technology will soon be far exceeded by market demand. Alternative production methods have recently attracted great attention. Among them, electrochemical lithium recovery, based on electrochemical ion‐pumping technology, offers higher capacity production, it does not require the use of chemicals for the regeneration of the materials, reduces the consumption of water and the production of chemical wastes, and allows the production rate to be controlled, attending to the market demand. Here, this technology is analyzed with a special focus on the methodology, materials employed, and reactor designs. The state‐of‐the‐art is reevaluated from a critical perspective and the viability of the different proposed methodologies analyzed.

Currently, Li is mainly produced from Li‐rich brines through the lime–soda evaporation process, which requires a long time and several purification steps, and has a severe environmental impact. Herein, ion‐pumping technology based on λ‐MnO2 as lithium‐capturing electrode is presented. The method has high lithium selectivity and can increase the lithium purity from 4.1 to 96 % in a single step. In addition, the time required to achieve the target lithium concentration (5000 ppm) can be reduced from the 12–14 months needed for the lime–soda evaporation process to less than 7.4 h. The small volume of water required, the absence of any chemical reactant, the recyclability of the used electrodes, and the possibility to combine ion‐pumping technology with renewable energy sources makes this process a potential ecofriendly alternative to the current lithium‐recovery methods.

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.