Traditional Li batteries utilizing graphite as an anode material face significant challenges when operating in cold temperatures, particularly below freezing. Graphite’s storage capacity decreases, and the formation of dendrites on the anode surface during charging can pose safety risks, including thermal runaway and potential explosions. These drawbacks have paved the way for the development of alternative materials that can address these limitations and provide more efficient and safer battery performance.
The Korea Institute of Energy Research (KIER) has introduced SKIER-5, a redox-active metal-organic hybrid electrode material designed to overcome the shortcomings of graphite anodes in Li batteries operating in cold conditions as low as minus 20 degrees Celsius. Unlike graphite, SKIER-5 is a redox-active conductive metal-organic framework assembled from a trianthrene-based organic ligand and nickel ions. This unique composition allows SKIER-5 to interact with Li ions, triggering redox reactions involving electron transfer and leading to increased electron storage capacity.
Performance Comparison and Results
In comparative testing, SKIER-5 demonstrated remarkable performance improvements over graphite anodes. The discharge capacity of SKIER-5 at subzero temperatures was five times higher than that of graphite, achieving a discharge capacity of 440 mAh/g, surpassing graphite’s 375 mAh/g at room temperature. Even after 1,600 charge-discharge cycles, SKIER-5 showed a 1.5 times increase in capacity, reaching 600 mAh/g. This exceptional result defies the typical trend of decreasing capacity with repeated cycles, highlighting the longevity and durability of SKIER-5 as a battery anode material.
The redox mechanism of SKIER-5 was confirmed through high flux X-ray analysis at the Pohang Accelerator Laboratory. Unlike graphite, SKIER-5’s inclusion of nickel ions and heteroatoms-based organic ligands enables effective interaction with Li ions, facilitating redox reactions that enhance electron storage and discharge capacity. SKIER-5’s lower energy threshold for chemical reactions compared to graphite allows for stable performance in low-temperature environments where reaction rates traditionally decrease. Furthermore, first-principles calculations based on quantum chemistry validated the operational efficiency of SKIER-5, confirming its crystalline structure, lithium adsorption sites, theoretical capacity, and reaction voltage predictions.
The development of SKIER-5 as a redox-active metal-organic hybrid electrode material marks a significant advancement in the field of Li batteries. With its superior performance, stability, and safety profile even in extreme cold conditions, SKIER-5 has the potential to revolutionize the use of Li batteries in a wide range of applications, including electric vehicles, drones, and ultra-small electronic devices. As researchers continue to explore innovative materials and technologies, SKIER-5 stands out as a promising solution for enhancing battery efficiency and reliability in various industries.