The Discovery

Researchers at the Max Planck Institute for Polymer Research and the University of Cambridge have discovered that strong electric fields fundamentally change how water molecules behave — and not in the way scientists expected.

Under normal conditions, water dissociation (splitting into H+ and OH− ions) is an energy-driven process. The reaction needs a push. But inside electrochemical devices, where intense electric fields are present, the researchers found that dissociation becomes entropy-driven — exactly the opposite of what happens in ordinary water.

What Changes Under Electric Fields

The key findings, published in the Journal of the American Chemical Society:

• pH shifts dramatically: Water under intense electric fields can drop from a neutral pH of 7 to as low as pH 3 — highly acidic
• Molecular reordering: Electric fields force water molecules into a highly ordered arrangement that then breaks down, promoting dissociation
• Entropy, not energy: The increased molecular disorder after ions form is what drives the reaction forward, not a reduction in energy barriers

Why It Matters for Industry

This research has direct implications for several industrial processes:

• Hydrogen production: Water electrolysis is the foundation of green hydrogen. Understanding the true mechanism of water splitting could lead to more efficient electrolyzer designs
• Fuel cells: Proton exchange membrane (PEM) fuel cells depend on controlled water chemistry at electrode surfaces
• Catalyst design: The findings open new directions for designing catalysts that work with entropy rather than against energy barriers
• Battery technology: Aqueous batteries and supercapacitors operate in environments where these electric field effects are significant

What to Watch

Lead researcher Yair Litman and co-author Angelos Michaelides emphasize that existing models for electrochemical systems may need revision. Scientists and engineers designing water-based electrochemical devices should "consider not just energy, but entropy" when modeling reaction pathways. As electrolyzer and fuel cell manufacturing scales up globally, these fundamental insights could influence the next generation of designs.