As renewable energy technologies such as fuel cells and electrolyzers continue to advance, scientists are searching for safer and more affordable alternatives to lithium for carrying electric charge. A new physical model developed by researchers at the Massachusetts Institute of Technology (MIT) offers a major step forward by improving predictions of how protons move through metal oxides.

The breakthrough could accelerate the development of energy technologies that rely on protons as charge carriers, rather than lithium ions, which dominate today’s batteries. Demand for lithium has surged with the growth of electric vehicles and renewable energy storage, driving up costs and raising concerns over safety and environmental impact.

Figure 1. New Light on Proton Dynamics.

Protons—essentially hydrogen nuclei with no electrons—offer an appealing alternative. They are the simplest possible charge carriers and are central to technologies such as fuel cells and electrolyzers. The challenge lies in mobility: for protons to be useful, materials must allow them to move easily and efficiently.

Until now, protons have only been able to conduct charge through metal oxides at very high temperatures—above about 400 °C (752 °F). Replicating that performance at lower, more practical temperatures has remained out of reach, making MIT’s new model particularly significant. Figure 1 shows New Light on Proton Dynamics.

How protons move through metal oxides

Unlike other ions, protons lack electrons and instead embed themselves within the electron clouds of nearby atoms. In metal oxides, they bond with oxygen ions, forming a covalent hydrogen–oxygen bond.

To move, a proton hops from one oxygen ion to the next using a hydrogen bond. During this process, the original covalent bond rotates, preventing the proton from simply slipping back to where it started. This subtle dance of bonding and rebonding governs how easily protons can travel through a material.

“Proton conductors are critical for a wide range of energy conversion technologies, from clean electricity and fuels to sustainable industrial chemistry,” said Bilge Yildiz, a professor in MIT’s Department of Materials Science and Engineering. “Scalable, inorganic proton conductors that work at room temperature are also important for energy-efficient, brain-inspired computing.”

A new way to predict proton mobility

Led by Yildiz, the MIT team focused on the flexibility of the oxygen-ion sublattice within metal oxides, suspecting it plays a crucial role in proton transport [1]. To quantify this effect, they introduced a new metric called oxygen–oxygen (O…O) fluctuation, which measures how the spacing between oxygen ions changes due to lattice vibrations, or phonons, at finite temperatures.

The researchers also identified seven key material features that influence proton mobility and compiled them into a comprehensive dataset. Using this information, they trained an artificial intelligence model capable of predicting how different metal oxides would respond to proton conduction.

Guiding the search for new materials

The model revealed that two factors dominate proton mobility: hydrogen bond length and oxygen sublattice flexibility. Shorter hydrogen bonds enable faster proton transfer, while more flexible oxygen networks make it easier for protons to move through the material.

Beyond improving predictions, the researchers believe their dataset could be used to screen massive materials databases—and even guide generative AI systems to design entirely new compounds optimized for proton transport.

“Large materials databases generated by organizations like Google and Microsoft could be searched using the relationships we’ve identified,” Yildiz said. “And if suitable compounds don’t already exist, these parameters could help generate new ones.”

Such advances could boost the efficiency and practicality of clean energy conversion technologies and pave the way for low-power computing systems that rely on protons rather than electrons.

References:

1. https://interestingengineering.com/science/mit-model-help-advance-proton-movement

Cite this article:

Keerthana S (2025), MIT Study Sheds New Light on Proton Dynamics Inside Metal Oxides, AnaTechMaz, pp.312