South Korea Polymer Silicon Anode 2023 Research

Monday - August 7 2023, 20:54 UTC - 1 year ago

Korean researchers have developed a new polymer binding material for the anode of batteries using silicon. This new material is more stable and reliable than previous materials and offers a greater energy capacity. Companies like Tesla and Amprius have already started using the new materials in their batteries with the potential of a 30% increase in energy density.

Korean researchers developed charged polymeric binder for a high-capacity anode material that is both stable and reliable, offering a capacity that is 10 times or higher than that of conventional graphite anodes. This breakthrough was achieved by replacing graphite with Si anode combined with layering-charged polymers while maintaining stability and reliability. The research results were published as the Front Cover Article in Advanced Functional Materials .

If there is more silicon in a battery anode then it has more energy. However, silicon expands and can reduce the number of times the anode can be charged and with too much expansion it can break the battery entirely. In 2023, Tesla has reportedly added up to 5 percent silicon in its batteries’ anodes.Benefits and the Major Challenge of Silicon in AnodesThe reaction mechanism of silicon with lithium is via intermetallic alloying .

This reaction allows silicon to provide almost ten times higher capacity (3600 mAh/g) than graphite (372 mAh/g) with the same weight. Using more silicon-based anodes has improved energy density by at least by 30 % of actual values.Anode manufacturers are introducing silicon into the electrodes but at rather low weight percentages of around 3 to 8 %, due to the complexities presented by silicon during the cycling of the battery: silicon particles undergo enormous volume changes, i .

e., up to 300 % of volume expansion (while in the case of graphite it is 13 %).CIC energiGUNE has published scientific results with high content silicon anodes (30 – 40 weight percentage of silicon at electrode level).There are companies like Amprius and OneD trying to use nanowires. Nanowires are a good alternative to conventional flat and round morphologies since volume changes are almost negligible because nanowires leave room for expansion .

Researchers are using CMC for binders that can handle the expansion of more silicon.There have been about 13000 published articles related to silicon-based anodes in the first half of 2023.South Korea Polymer Silicon Anode 2023 ResearchResearch to date has focused solely on chemical crosslinking and hydrogen bonding. Chemical crosslinking involves covalent bonding between binder molecules, making them solid but has a fatal flaw: once broken, the bonds cannot be restored .

Hydrogen bonding is a reversible secondary bonding between molecules based on electronegativity differences, but its strength (10-65 kJ/mol) is relatively weak.The new polymer developed by the research team not only utilizes hydrogen bonding but also takes advantage of Coulombic forces (attraction between positive and negative charges). These forces have a strength of 250 kJ/mol, much higher than that for hydrogen bonding, yet they are reversible, making it easy to control volumetric expansion .

The surface of high-capacity anode materials is mostly negatively charged, and the layering-charged polymers are arrayed alternately with positive and negative charges to effectively bind with the anode. Furthermore, the team introduced polyethylene glycol to regulate the physical properties and facilitate Li-ion diffusion, resulting in the low-cost and stable cycling performance of an anode with a silicon content of up to 40% .