New publication
Storage of renewable energy is the most crucial element in the road to a sustainable future. For enabling the transition to a sustainable society, the development of better (lithium) batteries is essential. Important factors for a viable energy storage solution are capacity, safety, cyclability and availability of component materials. In solid state batteries the liquid electrolyte separating the electrodes is replaced by a solid material which offers a number of advantages. Among these, a hybrid solid electrolyte that consists of both inorganic and organic solid electrolytes is most promising. However, the room-temperature conductivity of these hybrid solid electrolytes is still insufficient to support the required battery performance.
In an article describing the investigation of such a hybrid solid state electrolyte, researchers from TU Delft and Radboud University have been able to pinpoint the bottle-neck in the lithium ion conduction and have investigated ways of improving the hybrid electrolyte by using Nuclear Magnetic Resonance (NMR) methods.
Bottleneck
It was found that in a hybrid solid electrolyte comprised of polyethylene oxide polymer and the inorganic argyrodite Li6PS5Cl the bottleneck for lithium diffusion is across the organic–inorganic phase boundaries. At this interface, the deficiency of ethereal oxygen species and absence of local mobility are held responsible for the poor local Li-ion conductivity. By introducing two representative types of ionic liquid that have different miscibilities with the polymer they attempted to tailor the local environment at the interface between the inorganic and organic solid electrolyte components with the aim to reduce the interfacial barrier for the lithium ions.
Conductivity
The readily miscible ionic liquid was expected to only effect bulk polymer mobility while the poorly miscible ionic liquid would wet the polymer–inorganic interface and increase the local polarizability. Using a variety of NMR techniques they could indeed show this was the case; the poorly miscible ionic liquid resided at the interface. The enhanced cross-interfacial ion dynamics could be demonstrated and quantified with two dimensional lithium NMR exchange experiments. By adding this ionic liquid the diffusional barrier is lowered, which activates the high conductivity of the inorganic solid electrolyte phase in the hybrid solid electrolyte, resulting in an overall room temperature conductivity of 2.47 ´ 10-4 S/cm.
By revealing the bottleneck for Li-ion transport in hybrid solid electrolytes as well as unravelling the mechanism behind the targeted modification of the interface by using solid state NMR methodologies, new strategies are proposed, supporting design of future solid state electrolytes.
Magnetic Resonance Research Centre
Ernst van Eck is Assistant Professor at the Magnetic Resonance Research Centre within the Institute for Molecules and Materials (IMM) at Radboud University. The general mission of our group is to develop new techniques to optimize sensitivity and information content of NMR spectra and to apply these methods to target specific topics in materials research in terms of local structure and dynamics addressing structure/function relationships. Van Eck is particularly interested in sustainability and renewable energy. He uses solid state NMR techniques to gain insight into the structure and dynamics of battery materials. Next to energy storage issues he also has a keen interest in the conversion of biomass into chemicals as well as material science challenges relevant to the hydrogen economy.
Article information
Improving Li-ion interfacial transport in hybrid solid electrolytes
Ming Liu, Shengnan Zhang, Ernst R. H. van Eck, Chao Wang, Swapna Ganapathy and Marnix Wagemaker
Nat. Nanotechnol. (2022)
https://doi.org/10.1038/s41565-022-01162-9(verwijst naar een andere website)
More information?
For more information, please contact
Ernst van Eck erhve@science.ru.nl