Proton‑Friendly Oxides: How Oxygen Makes Fast Energy Storage Work

Scientists are looking for ways to store energy quickly and safely. One idea is to use tiny hydrogen ions, called protons, as the moving charge in batteries. Protons can move fast through solid materials, which could let a battery charge and discharge almost instantly. The big problem is that not many solid materials can hold protons easily. Researchers studied a family of compounds called VO2, which are transition‑metal oxides. These materials have different crystal structures that change how the atoms sit together. They found that protons like to sit next to oxygen atoms that are not surrounded by many other atoms. These less‑coordinated sites give the proton a lower energy and make it easier to fit in. Because of this preference, protons can hop from one site to another more smoothly.Another key discovery is that the oxygen atoms in VO2 can form a chain of hydrogen bonds. This network lets protons jump from one oxygen to the next in a way similar to how water molecules move. The process is called a Grotthuss‑like mechanism and it speeds up the overall transport of charge. Putting these two facts together, the study shows that the local oxygen environment is crucial for designing new materials that can host protons. If engineers create oxides with many low‑coordination oxygen sites and continuous hydrogen‑bond networks, they could build batteries that charge fast and store a lot of energy.