LAKE WALES, Fla. — Want to boost your lithium-ion battery’s lifetime without setting the house on fire? Taiwan’s Industrial Technology Research Institute (ITRI, Hsinchu) is proposing a quick-fix solution: a composite paste that OEMs can apply to battery electrodes. ITRI claims, with the test data to support it, that its ChemSEI-Linker paste increases Li-ion batteries’ lifetime up to 70%. ITRI also says ChemSEI-Linker is a green technology because it enables easier recycling of Li-ion cells at the end of their extended lifetimes.
ITRI engineered the material after analyzing why the electrodes always seem to be the weak link that causes Li-ion batteries to fail in the field. (The researchers looked at performance degradation, not the failures that result in fires or explosions; those have been traced to dendrites).
After surveying the literature and testing the most likely culprits in its labs, ITRI concluded that the primary cause of full-lifetime failure is the buildup of a predatory solid-electrolyte interface (SEI) layer starting with the very first recharge cycle. The buildup layer thickens over the lifetime of the battery, gradually degrading its performance until it works so poorly as to need replacement.
ITRI says ChemSEI-Linker inhibits that natural accumulation by depositing its own, nanoscale-thick SEI layer. The deposited SEI repels further buildup during recharging, much as depositing a single monolayer of oxidation on aluminum prevents more from accumulating and thereby makes the aluminum rust-free.
ITRI�s ChemSEI-Linker is an artificial nanoscale solid electrolyte interface of unique composition and structure that stabilizes lithium battery electrodes, increasing battery life by up 70%.
Image: ITRI
“Normal SEI formation is similar to the growing of tree rings. During each charging cycle, an irreversible electrochemical decomposition of the organic electrolyte happens at the electrode surface. This kind of decomposition deposits a layer with an increasingly complex composition on the surface of the active material, thus the name: solid-electrolyte interphase,” Jing-Pin Pan, chief technology officer of ITRI’s Material and Chemical Research Laboratories, told EE Times in an exclusive interview in advance of its Nov. 9 announcement. “The performance degradation results from the continuous SEI formation. As the SEI grows thicker, transportation of the lithium ion from the electrolyte to the active material becomes more difficult. Further, the lithium ion itself tends to be reduced on the SEI surface or intercalated within the SEI layer, leading to the loss of free lithium. Eventually, that loss leads to a positive potential shift of the anode, rendering the battery unusable.”
NEXT PAGE: New Methodology