Existence of the Cathode Electrolyte Interphase in Dual-Ion Batteries Investigated

Dual-ion batteries are considered a promising candidate for sustainable energy storage. Due to their high cell voltage, they have a suitable volumetric energy density. However, the elevated voltage increases the risk of material stress, particularly oxidative decomposition of the electrolyte. Modification and design of a suitable protective layer between the cathode and electrolyte, the Cathode Electrolyte Interphase (CEI), is a promising, but simultaneously not well understood and frequently controversial solution strategy. A team from MEET Battery Research Center at the University of Münster and Helmholtz Institute Münster of Forschungszentrum Jülich has now systematically investigated the existence of such an interphase on the graphite cathode of dual-ion batteries.

Surface of Graphite Cathode Without Signs of CEI Presence

Cost-effective and without toxic materials: Dual-ion batteries do not require critical raw materials such as nickel or cobalt, as graphite is also used for the cathode. “In our study, we discovered that the surfaces of these graphite cathodes surprisingly show no signs of CEI presence,” says MEET scientist Dr Lukas Haneke. “Dual-ion batteries are therefore promising high-voltage batteries, but need to be further investigated and developed.”

Dr Johannes Kasnatscheew, Head of the Research Division Materials at MEET Battery Research Center, also acknowledges that research and development of dual-ion batteries are complex: “There are still many unanswered questions, for example about relevance and impact of possible failure mechanisms on performance. The function and buildup of the CEI also needs to be further deciphered. Our results on metal-free cathodes have paved the way for this. They show that CEI formation does not always have to occur even if electrolyte oxidates.”

Detailed Results Online Available

The entire study has been published by the authors Dr Lukas Haneke, Katharina Rudolf, Pranti Sutar, Dr Tobias Placke and Dr Johannes Kasnatscheew, MEET Battery Research Center, Felix Pfeiffer and Dr Masoud Baghernejad, Helmholtz Institute Münster of Forschungszentrum Jülich as well as Prof. Dr Martin Winter, MEET Battery Research Center and Helmholtz Institute Münster, in the journal “Advanced Energy and Sustainability Research”.