posted on 2020-03-24, 13:33authored byPeter Benedek, Ola K. Forslund, Elisabetta Nocerino, Nuri Yazdani, Nami Matsubara, Yasmine Sassa, Fanni Jurànyi, Marisa Medarde, Mark Telling, Martin Månsson, Vanessa Wood
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.