South Korean scientists have recently achieved breakthroughs in the study of lithium batteries, and we are now one step closer to safe lithium batteries that contain a long lifespan thanks to the new ultra-high lithium metal battery.
The lithium metal battery is not quite the same as the lithium-ion batteries that we use nowadays. Despite being formed with lithium, cobalt, nickel, and manganese for the anode, the cathode has replaced the initial graphite and copper with lithium metal, and past researches indicate that using lithium metal as the cathode is able to double the capacity of power storage, followed by a significant increase in energy density.
However, this is more than a simple replacement of materials. Lithium metal contains a higher level of activity than sodium and magnesium, and is prone to an accumulation of lithium-ion during the charging and discharging process, followed by branch-like dendrites on the electrode surface due to uneven sedimentation. These dendrites would penetrate the insulation layer, and result in fire accidents from malfunctioning batteries. Hence, a number of research teams believe that the prevention of dendrite formation would require a layer of protection around the lithium, or a layer of solid electrolyte interface (SEI) between the cathode and electrolytes.
Professor Yong Min Lee at the Daegu Gyeongbuk Institute of Science and Technology (DGIST) pointed out that the formation of dendrites depends on the surface property of battery cathode, thus a key solution for lithium metal batteries is to create a layer of effective SEI. The research team of DGIST also managed to construct an ultra-thin composite electrode through Li metal powders (LMP).
LMPs are spherical particles that are able to elevate the surface area of electrode, and can be adjusted in thickness according to the requirements. The research team also discovered this time that lithium nitrate effectively resolves battery failure derived from uneven electrode surfaces, and managed to develop cathodes that are 150mm in width and 20µm in thickness, with a remaining capacity maintained at 87% after 450 charging and discharging cycles, as well as a coulombic efficiency of 96%.
DGIST scientists found out that the addition of lithium nitrate during the production process will create ultra-thin cathode, as well as SEI that has a smooth and even surface. Lee pointed out that the incorporation of stable additives in the LMP helps with the research and develop on lithium metal batteries, lithium-sulfur batteries, and lithium-air batteries that possess high specific energy and long cycle life.
(Cover photo source: shutterstock)