Quantifying Diffusion through Interfaces of Lithium-Ion Battery Active Materials

Abstract

Detailed understanding of charge diffusion processes in a lithium-ion battery is crucial to enable its systematic improvement. Experimental investigation of diffusion at the interface between active particles and the electrolyte is challenging but warrants investigation as it can introduce resistances that, for example, limit the charge and discharge rates. Here, we show an approach to study diffusion at interfaces using muon spin spectroscopy. By performing measurements on LiFePO4 platelets with different sizes, we determine how diffusion through the LiFePO4 (010) interface differs from that in the center of the particle (i.e., bulk diffusion). We perform ab initio calculations to aid the understanding of the results and show the relevance of our interfacial diffusion measurement to electrochemical performance through cyclic voltammetry measurements. These results indicate that surface engineering can be used to improve the performance of lithium-ion batteries.

Magnetism and ion diffusion in honeycomb layered oxide $${\hbox {K}_2\hbox {Ni}_2\hbox {TeO}_6}$$

“…S2 b) that display very different behaviour. Such data is coherent with our previous work on the well-known cathode material 26 , 29 , 39 , 40 , where we indeed have shown by both inelastic neutron scattering and SR that the self-diffusion of lithium ions is mainly limited to the surface region of the particles. Our current results indicate that the situation could be very similar also for .…”

“…battery materials. This can be conducted either indirectly via bulk SR techniques, like our current and previous studies 40 , or by the utilization of the low-energy SR (LEM) method that is able to directly probe the surface/interface properties via depth-resolved studies of thin-film and multi-layer samples 41 . To conclusively confirm the origin of the two KT functions as surface and bulk contributions, further theoretical calculations to robustly determine the muon sites along with additional systematic SR and potentially LEM studies of nano-structured samples with controllable size and surface will be required.…”

Na-ion mobility in P2-type Na0.5MgxNi0.17−xMn0.83O2 (0 ≤ x ≤ 0.07) from electrochemical and muon spin relaxation studies

“…The x = 0.02 sample even displays a lower activation energy than the well-known Li-ion cathode material LiFePO 4 , which displayed E a  100 meV in earlier  + SR studies. 38,40,56 This journal is © The Royal Society of Chemistry 20xx…”

“…About a decade ago the targeted application for studies of ion diffusion in energy related materials using  + SR was initiated through a collaboration between academia and industry when the first systematic study of Li-ion diffusion in the archetypical battery cathode material Li x CoO 2 was presented. 36 Since then,  + SR has been utilized to study charge dynamics within a broad range of Li/Na/K-ion battery cathodes [37][38][39][40] , anodes 41,42 and solid electrolytes 43,44 , as well as hydrogen diffusion/desorption in H-storage materials 45,46 , long with ion movement in photovoltaic materials 47 . Hence,  + SR has become a novel and unique method for the area of sustainable energy materials.…”

Self-assembled materials for electrochemical energy storage

“…59 Finally, Benedek et al were able to measure a drop in the diffusion activation barrier of the LiFePO4-carbon interface. 60 While all these initial experiments are promising, finding experimental designs to extend the techniques to more complex interface structures will be key.…”