New hybrid binder for lithium EV batteries retains 86% capacity after 200+ cycles

A South Korean team has designed a Dual-Acting Hybrid Polymer (DHP) binder for thick-film lithium-ion battery electrodes. Sungkyunkwan University and Seoul National University report that the novel binder enhances lithium-ion battery energy density and extends overall lifespan. It solves a common issue where the binder drifts and ruins battery performance when making thicker, higher-capacity electrodes for EVs and smartphones. In the testing, the binder demonstrated nearly double the adhesive strength compared to traditional PVDF binders. Structure of the DHP hybrid polymer binder and its principle for protecting the battery electrode. Credit: SKKU Combining two materials Range anxiety is real in electric vehicles. To push driving ranges past 400 miles, battery makers have been trying to make electrode layers much thicker. Thicker electrodes hold more power-dense materials like nickel. There is just one problem. The process falls apart during drying. When battery manufacturers apply liquid mixtures to build thick electrodes, standard glue, known as a polyvinylidene fluoride (PVDF) binder, floats to the top. As the slurry dries, the binder unevenly distributes. And the electrode cracks, crumbles, and fails to conduct electricity properly. It is a chronic roadblock. Batteries built this way degrade rapidly after a handful of charge cycles. “Previously, increasing electrode thickness and size was limited by binder and processing issues, which restricted overall battery performance. We overcame this hurdle by efficiently combining the advantages of spandex and poly(acrylic acid),” explained lead researcher Ki-Jae Kim, a professor at SKKU. The solution came from combining two materials with opposite skill sets: spandex (SPDX) and polyacrylic acid (PAA). And it was dubbed the Dual-Acting Hybrid Polymer (DHP) binder. It works instantly. Spandex brings flexibility. Its high elasticity gives the thick electrode the structural resilience it needs to resist snapping or fracturing under stress. PAA brings chemical strength and forms tight molecular bonds with internal battery components. During initial charge cycles, the hybrid binder does something even better: it spontaneously forms a special lithium-interface layer. This highway speeds up lithium-ion movement straight through the dense material. Shows promise in testing The numbers speak for themselves. The new hybrid glue delivers nearly twice the adhesive strength of PVDF. In tests using commercial-grade pouch cells, conventional thick batteries collapsed after roughly 95 cycles. On the other hand, pouch cells using the spandex-infused binder maintained 86.8 percent of their original capacity past 200 cycles. Interestingly, this jump in cycle life enhances the battery’s operational lifespan. The best news for the automotive industry is not just what the binder does. It is how it can be made. Many next-generation battery developments require entirely new factories. It demands expensive dry-processing equipment or radical tooling overhauls. This binder does not. It fits directly into existing wet manufacturing lines. Factory owners can swap the chemical glue without buying a single new machine or pausing assembly. “This binder technology is highly adaptable for industry because it uses existing wet production lines without adopting dry-processing technologies, which have recently attracted attention as next-generation battery manufacturing methods. We expect it to play a pivotal role in extending the driving range of next-generation electric vehicles,” Kim concluded. The study findings were published in the journal Nature Communications. Recommended ArticlesGet the latest in engineering, tech, space & science - delivered daily to your inbox.Mrigakshi is a science journalist who enjoys writing about space exploration, biology, and technological innovations. Her work has been featured in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy magazine. If you have pitches in mind, please do not hesitate to email her.