Scientists from South Korea have unveiled a novel electrode additive that could increase the lifespan and fast chargeability of high-energy-density lithium-ion batteries.
A team from the Department of Chemistry at Ulsan National Institute of Science and Technology (UNIST) created a stable and spatially deformable solid electrolyte interphase on a high-capacity silicon carbide (Si–C) anode.
The researchers made the discovery when exploring large-capacity materials, such as silicon or nickel, as a replacement material for conventional lithium-ion battery electrodes.
They found the new anode could tolerate volume changes induced by the lithiation of silicon, and could enable a long lifespan and fast chargeability of high-energy-density lithium-ion batteries.
Silicon can improve the energy density of lithium-ion batteries, but it exhibits poor mechanical strength due to volumetric expansion during cycling. High- nickel (Ni) cathode materials also suffer from poor chemical stability.
The findings were published in the February issue of Nature Communications journal.
According to the research team, when the new additives were added to a large-capacity battery composed of high-Ni anodes and a Si-mixed anode, the initial capacity was maintained at 81.5% after 400 cycles— 10% to 30% better than the choice of VC (vinylene carbonate) or FEC (fluoroethylene carbonate), as additive.
The research was carried out by professor Nam-Soon Choi and professor Sang Kyu Kwak in the School of Energy and Chemical Engineering, in collaboration with professor Sung You Hong in the Department of Chemistry at UNIST.
It has also been participated by professor Jaephil Cho in the School of Energy and Chemical Engineering at UNIST.
Professor Choi, co-corresponding author of the study, said: “This achievement is the result of the collaboration of material structure design, experiment, simulation, and synthesis method research to actually make this material structure that can compensate for the shortcomings of existing additives (VC). It suggested a new direction for the development.”
In addition, the research team also found that these additives could remove hydrofluoric acid (HF) from the electrolyte to prevent the metal (nickel) inside the high-Ni anodes from leaking out. The amount of metal inside the anode determines the battery capacity.