Aluminum alloy, ultra-thin MoS
Resolution of lithium anode instability
Increased battery life through electrolyte optimization


The development of 'lithium metal batteries,' a next-generation battery system known to have a theoretical energy density about 10 times higher than that of lithium-ion batteries, is gaining momentum again.

The Korea Institute of Science and Technology (KIST) announced on the 18th that its research team has developed a lithium-aluminum alloy-based anode material that eliminates the physicochemical instability of lithium metal batteries.

Dr. Wonil Cho's team at the Energy Storage Research Group, which developed the cathode material, also succeeded in optimizing the electrolyte system to extend the lifespan by more than double compared to previously developed lithium-ion batteries.

A lithium metal battery is a battery that uses lithium metal as the negative electrode.

Lithium metal possesses the highest energy density among cathode materials identified to date. On the other hand, its very low redox potential has made it a highly anticipated material suitable for secondary batteries requiring lightweight and high capacity.

However, due to the possibility of electrode short circuits and explosions caused by dendrites occurring on the surface of lithium metal, lithium-ion batteries using graphite anodes were commercialized first.

Dendrites are tree-branch-shaped crystals that grow abnormally on parts of a metal surface, causing electrode volume expansion and adverse reactions between the electrode and the electrolyte, thereby reducing the safety and lifespan of the battery.

Lithium-ion batteries are recently assessed to have reached a limit where it is difficult to further increase energy density per unit weight. On the other hand, as there is a demand for higher-performance, high-capacity batteries in various fields such as electric vehicles and drones, research to ensure the electrochemical stability of lithium metal anodes is actively underway worldwide.

Researchers at KIST replaced the existing pure lithium metal anode with a lithium-aluminum alloy to control instability, while forming an ultra-thin artificial protective film based on molybdenum disulfide (MoS) on the anode surface to suppress the growth of dendrites that rapidly degrade battery capacity and lifespan.

The ultrathin artificial protective film is an artificial solid-electrolyte interphase developed by Dr. Won-il Cho. The artificial solid-electrolyte interface is a thin layer ranging from several to thousands of nanometers in thickness that is artificially created on the surface of the anode or cathode to control the reaction occurring between each electrode and the electrolyte, and last year, its performance and stability were proven by evenly transferring graphene-based nanomaterials onto the surface of lithium metal.

In this study, research efforts were focused on lowering costs by using molybdenum disulfide and lithium-aluminum alloy instead of graphene to ensure the actual mass production feasibility of ultrathin artificial protective films, as well as simplifying complex manufacturing processes and stabilizing the battery.

Dr. Wonil Cho of KIST stated, “As the capacity limits of existing lithium-ion batteries are anticipated, the demand for the development of lithium-metal batteries is increasing,” adding, “I hope that lithium anode stabilization and electrolyte technologies, which are key to the development of next-generation rechargeable batteries, will contribute to the advancement of drones, autonomous vehicles, and energy storage systems (ESS) that require high-capacity batteries.”