Osmotic energy, often hailed as blue energy, is quickly emerging as a game-changing renewable energy source that can harness the immense power generated by the natural difference in salt concentration between seawater and freshwater. This energy form exploits the voltage that develops when ions selectively move across ion-permeable membranes from saltier to less salty environments. Though promising in theory, practical implementation has long been hindered by a fundamental technological challenge: creating membranes that simultaneously offer high ion selectivity and rapid ion transport. Traditionally, membranes that excel in allowing ions to flow quickly often sacrifice selectivity, while highly selective membranes suffer from slow ion transfer rates. These limitations, coupled with the difficulty in maintaining charge separation and membrane durability under operational conditions, have confined osmotic energy technology predominantly to laboratory explorations rather than real-world applications.
A recent breakthrough by researchers at EPFL’s Laboratory for Nanoscale Biology (LBEN), under the leadership of Aleksandra Radenovic, is poised to shift this paradigm. Collaboratively working with the Interdisciplinary Centre for Electron Microscopy (CIME), the research team has published compelling findings in the prestigious journal Nature Energy, revealing an innovative approach that surmounts the longstanding obstacles in osmotic power generation. Their strategy involves the use of lipid-based nanostructures—specifically, lipid bilayer coatings deposited on nanopores—to render ion channels that brilliantly combine selectivity with high transport speeds. These lipid bilayers, analogues to natural cell membrane components, create a lubricating environment that drastically reduces ion friction and facilitates efficient passage of target ions.
In this study, the scientists engineered nanofluidic channels constituted by silicon nitride membranes perforated with stalactite-shaped nanopores. These nanopores, when unmodified, permitted controlled yet sluggish ion migration due to restricted flow paths and high frictional interactions. The team’s innovation was to coat these nanopores with self-assembled lipid bilayers composed of amphiphilic molecules with hydrophilic heads and hydrophobic tails. The outer hydrophilic heads attract an ultra-thin hydration layer just a few molecules thick, which serves as a frictionless water lubricating film, enabling ions to slip through with reduced resistance. This nano–hydration lubrication mechanism effectively decouples ion flow speed from ion selectivity constraints—a critical advance that had eluded researchers until now.
To validate their approach’s real-world relevance, the group fabricated membranes containing an array of 1,000 such lipid-coated nanopores arranged in a highly ordered hexagonal pattern. The device was tested under simulated natural conditions, mimicking the salt gradients found where rivers meet the ocean. Remarkably, the energy conversion performance exhibited an overall power density of approximately 15 watts per square meter. This output surpasses conventional polymer membrane technologies by a factor of two to three, positioning this nanoscale strategy as a highly competitive and scalable solution for osmotic energy harvesting.
While earlier computational models had suggested the possibility of simultaneously enhancing ion selectivity and throughput by precisely tuning surface charges and nanopore geometries, real experimental realization was scarce. This research signifies an experimental milestone, showcasing that thoughtfully engineered nanofluidic pores, combined with lipid bilayer lubrication, can redefine ion transport characteristics fundamentally. The ability to simultaneously mitigate friction and sustain charge-based selectivity has propelled osmotic energy conversion beyond a mere proof of concept towards practical, high-performing devices.
The implications of this work extend well beyond blue energy applications. The “hydration lubrication” principle demonstrated here hinges on fundamental physicochemical interactions intrinsic to lipid bilayers and nanoscale confinement, implying that similar lipid-coated nanofluidic platforms could optimize a range of ionic transport systems. This universality suggests future explorations might harness such architectures to improve efficiency in biosensors, desalination membranes, and electrochemical devices, among others.
Key to this endeavor’s success was access to advanced characterization tools and fabrication facilities at EPFL. The intricate morphology and chemical composition of the lipid-coated nanopores were elucidated through high-resolution electron microscopy performed by Dr. Victor Boureau and colleagues at CIME. These diagnostics verified the uniformity and robustness of the lipid bilayers, as well as their nanoscale interactions with the substrate, providing essential insights into optimizing coating protocols.
Additionally, EPFL’s state-of-the-art nanofabrication infrastructure enabled the precise creation of silicon nitride membranes with controlled nanopore structures. Complemented by high-performance computational modeling, the interdisciplinary collaboration bridged nanoscale design and experimental validation, resulting in a cohesive, scalable nanofluidic platform. This synergy between fabrication, characterization, and simulation heralds a new era where osmotic power devices can be systematically designed rather than empirically optimized.
According to lead scientist Aleksandra Radenovic, their approach merges two previously distinct technological directions: polymer membranes promising wide-area scalability, and nanofluidic channels offering molecular-scale control over ionic transport. By integrating the broad, porous membrane architecture with nanopores tailored through surface chemistry and lubrication, the researchers achieved a breakthrough in converting salinity differences into usable electrical energy with unprecedented efficiency.
The first author, Yunfei Teng, emphasizes that beyond blue energy, hydration lubrication could be a versatile design principle in nanofluidics. By fostering a hydration layer that dramatically reduces friction, membranes could maintain high performance under demanding conditions and potentially prolong operational lifetimes. This discovery suggests a path to overcome membrane fouling issues and mechanical degradation, which commonly limit the durability of current osmotic energy systems.
This novel lipid bilayer coating method, by enabling enhanced ion slip and charge control, fundamentally reshapes the understanding of ion selectivity and transport in confined nanoscale channels. As the researchers demonstrate, fine-tuning nanopore shape and surface charge distributions in conjunction with the lubrication effect unlocks new parameters for optimizing power density and device robustness. Such mechanistic control is pivotal for translating laboratory successes into industrially viable osmotic generators.
Looking forward, the team’s work lays the foundation for deploying nanopore-based osmotic energy devices in real environmental settings, such as estuaries where fresh and saltwater naturally blend. Scaling the technology up while ensuring material stability and cost-effectiveness will be crucial next steps. Nevertheless, the reported enhancement in power output and operational principles establish a clear roadmap for industrial adoption of nanofluidic blue energy harvesters.
This study heralds a significant stride towards sustainable, environmentally friendly electricity production from abundant natural resources, pushing the frontiers of nanotechnology and membrane science. By merging biomimetic lipid structures with advanced nanofluidics, the researchers have charted a promising route to realize practical osmotic energy conversion systems capable of contributing meaningfully to the global renewable energy portfolio.
Subject of Research: Osmotic energy harvesting via lipid-bilayer-coated nanofluidic membranes
Article Title: Charge and slip-length optimization in lipid-bilayer-coated nanofluidics for enhanced osmotic energy harvesting
News Publication Date: 16-Feb-2026
Web References:
https://www.nature.com/articles/s41560-026-01976-0
References:
Article published in Nature Energy, 2026, DOI: 10.1038/s41560-026-01976-0
Keywords
Electrical power, Ion-selective membranes, Nanofluidics, Osmotic energy, Blue energy, Lipid bilayers, Nanopores, Hydration lubrication, Renewable energy, Nanotechnology, Membrane science, Energy conversion
Tags: blue energy innovationsbreakthroughs in osmotic powerEPFL Laboratory for Nanoscale Biologyhigh ion transport solutionsinterdisciplinary energy research collaborationsion-permeable membrane developmentsion-selective membranes researchmembrane durability challengesosmotic energy technologiesrenewable energy advancementssaltwater energy harnessingsustainable energy generation methods
