A three-year project by the U.S. Department of Energy’s (DOE) Argonne National Laboratory, in collaboration with Hong Kong University of Science and Technology (HKUST) has made a breakthrough in improving lithium-ion batteries.
Researchers used a coating called PEDOT to completely protect each particle of the cathode — inside and out — from reacting with the electrolyte, which improves lithium-ion battery cycle life and safety.
Traditional lithium battery cathode coating technology only covers a small part of the outside of the cathode particle and does not protect the cathode when operating at a high voltage or at high temperature, say DOE researchers.
The new coating, made with poly(3,4-ethylenedioxythiophene) facilitates the transport of lithium ions and electrons in and out of the cathode, which helps boost battery energy. It is was applied using Argonne’s oxidative chemical vapor deposition technique, which uses gas to ensure the coating is applied to every particle of the cathode, forming a robust skin.
The coating can help increase the voltage of lithium-ion batteries by 0.4V to 4.6 V.
The project was funded by the DOE’s Office of Renewable Energy and Energy Efficiency, Vehicle Technologies Office. The initial experiment was conducted in Hong Kong.
Khalil Amine, Argonne distinguished fellow, said: “This is an incredibly exciting advancement. This could significantly improve our experience with the devices we’ve come to rely on.
“This would increase the driving range of electric cars and boost the battery life of cell phones and laptops, ultimately changing the way we live.”
Researchers used CNM’s Zeiss NVision 40 focused ion beam-scanning electron microscopy dual-beam system and FEI Talos F200X (S)TEM equipped with a SuperX energy-dispersive X-ray spectrometer to confirm the coating of PEDOT on both primary and secondary particles of layered cathodes and their stability after battery cycling.
A paper on the topic was published in Advanced Energy Materials in December 2019, and another published in the journal Nature in May 2019.
Image: PEDOT is coated on both primary and secondary particles of NMC cathode used in EVs. This coating protects the cathode against reactivity with electrolyte and extends the life of the battery. (Image by Argonne National Laboratory.)
