Schematic of a silicon anode material enabling high-energy, fast-charging EV batteries. Provided by POSTECH
Silicon, considered a “dream material” for electric vehicle (EV) batteries, has a fatal weakness: it swells and fractures every time it is charged and discharged. A Korean research team has overcome this challenge through precise nanoscale crystal design. This brings EVs capable of driving 1,000 km on a single charge a step closer.
On the 1st, POSTECH announced that a research team led by Professor Soo-Jin Park and Dr. Min-Jun Je of the Department of Chemistry, in collaboration with Professor Jang Wook Choi’s group in the School of Chemical and Biological Engineering at Seoul National University and LG Energy Solution, has succeeded in developing a high-strength silicon anode material that does not fracture even after repeated charge–discharge cycles in secondary batteries. The research was published on April 24 in the international journal Nature Communications.
The competitiveness of an electric vehicle is determined by its battery. The key questions are how far it can travel on a single charge and how quickly it can be recharged. Graphite, the most widely used anode material in current EV batteries, has already reached its theoretical limit in energy storage. Silicon is emerging as the leading alternative.
Silicon can store up to 10 times more energy than graphite, which is why it is called a “dream material.” However, during repeated charging and discharging, its volume expands and contracts by up to 300%. Just as a balloon eventually bursts if you keep inflating it, silicon particles crack or break apart. This leads to performance degradation and shorter battery life, and has been the biggest obstacle to the commercialization of silicon anodes.
While previous studies mainly focused on simply making the material “harder,” the research team focused on the “strength” needed to withstand repeated volume changes. The goal was not glass that easily shatters, but a metal-like material that bends and then returns to its original shape.
The team precisely embedded lithium fluoride (LiF) crystals 32 nanometers (nm, 1 nm is one-billionth of a meter) in size inside silicon oxide. The design applies the “Hall–Petch relationship”—where smaller crystals increase strength—and the “inverse Hall–Petch effect,” where crystals that become too small instead weaken the material. In addition, they formed a special coating layer on the particle surface that allows ions to pass smoothly while enabling fast electron transport, thereby achieving fast-charging performance.
Experiments showed that the volume change during charge and discharge for the developed material was limited to 18.9%. Compared with the 300% expansion of conventional silicon, this is effectively negligible. In actual cell tests, the batteries operated stably for more than 1,000 cycles under 20-minute fast-charging conditions (10–80% state of charge).
In a 1.26 ampere-hour (Ah) pouch-type battery, stable operation was confirmed for more than 500 cycles. The energy density reached 402 watt-hours (Wh) per kilogram and 1,125 watt-hours per liter, significantly higher than that of currently commercialized EV batteries.
The researchers explained that applying this technology to real electric vehicles could enable the development of EVs capable of traveling about 1,000 km on a single charge. This would provide the technological foundation to alleviate “range anxiety” for drivers in regions with limited charging infrastructure or those who frequently drive long distances.
Professor Soo-Jin Park of POSTECH said, “We solved the fracture problem of silicon anodes by simultaneously increasing strength and Young’s modulus (a measure of material stiffness),” adding, “This will help accelerate the commercialization of next-generation batteries that combine high energy density with fast charging.”
Professor Jang Wook Choi of Seoul National University emphasized the significance of the work, saying, “The key was to maximize performance by precisely controlling the crystal size at the nanometer scale.”
doi.org/10.1038/s41467-026-72434-4
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