Seoul National University · Engineering
Professor Youngmin Ko's research lab specializes in advancing next-generation energy storage systems, with a primary focus on lithium–oxygen batteries. The lab investigates redox mediators, catalyst design, and electrolyte engineering to overcome key challenges such as high polarization, poor cyclability, and electrolyte degradation. By drawing inspiration from biological electron transfer systems and developing innovative polymer-anchored redox mediators, the lab aims to decouple charge transport from shuttle degradation, enabling high-energy and high-power battery performance. The group also explores novel electrolyte additives and interphase stabilization strategies, particularly for silicon anodes, to enhance long-term battery stability.
Figures are computed from collected data and may differ slightly.
Abstract Governing the fundamental reaction in lithium–oxygen batteries is vital to realizing their potentially high energy density. Here, novel oxygen reduction reaction (ORR) catalysts capable of mediating the lithium and oxygen reaction within a solution‐driven discharge, which promotes the solution‐phase formation of lithium peroxide (Li 2 O 2 ), are reported, thus enhancing the discharge capacity. The new catalysts are derived from mimicking the biological redox mediation in the electron tr
Redox mediators (RMs) are considered an effective countermeasure to reduce the large polarization in lithium-oxygen batteries. Nevertheless, achieving sufficient enhancement of the cyclability is limited by the trade-offs of freely mobile RMs, which are beneficial for charge transport but also trigger the shuttling phenomenon. Here, we successfully decoupled the charge-carrying redox property of RMs and shuttling phenomenon by anchoring the RMs in polymer form, where physical RM migration was re
For the realization of high-power lithium–oxygen batteries, a comparative study was conducted to investigate the kinetic properties of redox mediators.
Unlike most anodes used in high energy density batteries, lithiated Si does not form long-lasting passivating solid-electrolyte interphases (SEI) during formation or on charge due to SEI delamination, reconstruction, or dissolution. As a result, electrolyte degradation is continuous and results in a permanent loss of the Li inventory, shortening the useful life of the battery. Here, we show that perfluoroether electrolyte additives featuring either sulfonyl fluorides or trifluorovinyl ethers, wh
Intrinsic properties of quinones such as steric hindrance and heterogeneous electron transfer kinetics that follows Marcus theory concurrently govern their performance as redox mediators for oxygen reduction reactions in lithium–oxygen batteries.
Abstract The discovery of a reliable electrolyte system remains one of the key challenges for the development of advanced lithium–oxygen batteries. To date, no single electrolyte is verified to be stable and compatible with both the cathode (e.g., oxygen radicals, lithium peroxide, etc.) and anode (lithium metal) for lithium–oxygen batteries. In this work, a novel liquid‐based Janus electrolyte system consisting of two different immiscible liquid phases is proposed and it is demonstrated that th
Abstract Redox mediators (RMs) are considered an effective countermeasure to reduce the large polarization in lithium‐oxygen batteries. Nevertheless, achieving sufficient enhancement of the cyclability is limited by the trade‐offs of freely mobile RMs, which are beneficial for charge transport but also trigger the shuttling phenomenon. Here, we successfully decoupled the charge‐carrying redox property of RMs and shuttling phenomenon by anchoring the RMs in polymer form, where physical RM migrati
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