PERSPECTIVE article
Front. Chem.
Sec. Electrochemistry
Volume 13 - 2025 | doi: 10.3389/fchem.2025.1659479
This article is part of the Research TopicFlexible Energy Materials and DevicesView all articles
Blue Energy Recovery in the Atacama Desert Using Electrochemical Ion Pumping Devices: A Chilean Perspective on Salinity Gradient Energy
Provisionally accepted
Felipe M. Galleguillos Madrid1,2*
Sebastián Salazar Avalos1,2MARKUS BERGEDAHL1,2Javier Quispe3
Norman Toro4Galvarino Casanueva Yañez5
Alvaro Soliz6- 1University of Antofagasta, Antofagasta, Chile
- 2Universidad de Antofagasta Centro de Desarrollo Energetico Antofagasta, Antofagasta, Chile
- 3Universidad Catolica del Norte, Antofagasta, Chile
- 4Universidad Arturo Prat, Iquique, Chile
- 5Universidad de Las Americas, Santiago, Chile
- 6Universidad de Atacama, Copiapó, Chile
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The growing global demand for clean and sustainable energy has intensified the development of novel technologies capable of harnessing naturally available resources. Among these, blue energy, referring to the power generated from the mixing of waters with different salinities, has emerged as a promising yet underutilized source. This perspective presents a comprehensive synthesis of recent advances in electrochemical harvesting systems, with a particular focus on Mixing Entropy Batteries (MEBs) as efficient, membrane-free devices for salinity gradient energy recovery. Unlike conventional approaches such as Reverse Electrodialysis (RED) and Pressure Retarded Osmosis (PRO), which depend heavily on ion-exchange membranes and complex infrastructure, MEBs offer simplified and scalable architecture suitable for harsh environments and industrial effluents. The use of LiCl-based electrolytes enables significant blue energy recovery, achieving energy densities of 38.2 mJ/cm² and power densities of 13.8 μW/cm², with excellent cycling stability. This system leverages the high solubility of LiCl (832 g/L) to create steep salinity gradients, utilizing LiFePO₄/FePO₄ as the cathode and Ag/AgCl as the anode, with no observable performance degradation over 100 cycles. This work analyzes alternative electrode materials, including Prussian Blue analogues (copper hexacyanoferrate CuHCF), MnO₂, BiOCl, and polypyrrole, and explores their integration with unconventional water sources such as industrial brines, hypersaline reject streams, and treated wastewater, particularly within the resource-constrained context of the Atacama Desert. This manuscript consolidates experimental data, device designs, and comparative performance metrics, providing a critical framework for advancing blue energy technologies. It also underscores their potential role in circular economy models and off-grid renewable energy
Keywords: blue energy, Mixing entropic battery (MEB), Salinity gradient energy, Electrochemical ion pumping, Atacama Desert, Brine
Received: 04 Jul 2025; Accepted: 08 Aug 2025.
Copyright: © 2025 M. Galleguillos Madrid, Avalos, BERGEDAHL, Quispe, Toro, Yañez and Soliz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Felipe M. Galleguillos Madrid, University of Antofagasta, Antofagasta, Chile
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