"United for Strength: Interconnected Electrodes Extend Silicon Battery Life Beyond Expectations"

As the need grows for batteries with higher energy storage and longer lifespans—essential for electric vehicles, drones, and large-scale energy systems—a team of researchers in South Korea has unveiled a revolutionary solution to a key flaw in conventional lithium-ion batteries: the unstable interface between electrodes and electrolytes.

Currently, most consumer devices like smartphones and laptops use graphite-based batteries. Although graphite is stable over long periods, it lacks high energy capacity. Silicon, on the other hand, can hold almost ten times more lithium ions, making it a strong contender for future battery anodes.

However, silicon's major issue lies in its significant expansion and contraction—up to three times its size—during charging and discharging cycles. This leads to physical gaps forming between the electrode and electrolyte, which rapidly reduces battery efficiency and longevity.

To combat this, scientists have experimented with replacing liquid electrolytes with solid or quasi-solid-state electrolytes (QSSEs), which offer improved safety and structural stability. However, these materials still face challenges in maintaining consistent contact with the silicon anode as it expands and contracts, resulting in separation and reduced performance over time.

In response, a joint research team from POSTECH (Pohang University of Science and Technology) and Sogang University has introduced an innovative In Situ Interlocking Electrode–Electrolyte (IEE) system. This system establishes covalent chemical bonds between the electrode and electrolyte, unlike traditional batteries where components merely make contact. The IEE design chemically interlocks the two components, similar to bricks bound by solid mortar, ensuring they stay firmly connected even under intense mechanical stress.

Electrochemical performance tests revealed a striking contrast: conventional batteries began to lose capacity after only a few charge-discharge cycles, whereas those incorporating the IEE design showed sustained long-term stability. Remarkably, the IEE-based pouch cell achieved an energy density of 403.7 Wh/kg and 1300 Wh/L—offering more than 60% higher gravimetric energy density and nearly double the volumetric energy density compared to standard commercial lithium-ion batteries. In real-world terms, this advancement allows electric vehicles to drive longer distances and smartphones to run for extended periods without increasing battery size.

“This research paves the way for future energy storage systems that require both high energy density and long-term reliability,” said Professor Soojin Park of POSTECH, a co-leader of the study. Professor Jaegeon Ryu of Sogang University added, “The IEE approach represents a breakthrough technology that could speed up the commercialization of silicon-based batteries by greatly improving interface stability.”

The study was conducted by a team led by Professor Soojin Park (Department of Chemistry, POSTECH), Dr. Dong-Yeob Han, Dr. Im-Kyung Han (Department of Materials Science, POSTECH), and Professor Jaegeon Ryu (Department of Chemical and Biomolecular Engineering, Sogang University). Their findings were recently published in Advanced Science, a leading scientific journal, with backing from the Korea Institute of Materials Science and the Korea Institute for Advancement of Technology.