Surface coatings to mitigate phase separation in LiFePO4 during lithium-ion battery discharge
Journal article, 2026
To achieve long-lasting, high-performance lithium-ion batteries, local inhomogeneity in current density must be avoided. One driver of such inhomogeneity is the spinodal decomposition of active materials into Li-rich and Li-poor phases during charge and discharge, respectively. Whether or not such phase separation occurs is linked to the dynamics of lithium (Li) at the active material surface and within its bulk. Here, we show that particle surface coatings can be designed to inhibit phase separation. Using LiFePO4 as a model system, we prepare particles with different coatings in order to tune Li dynamics and electronic structure and thereby induce or prevent phase separation, which we verify through experiment and ab initio calculations. We then leverage our findings to create a mixed ceramic-carbon coating that mitigates phase separation down to rates as low as 0.1C and simultaneously enables fast (dis)charge up to 5C.
lithium-ion batteries
phase separation
surface coating
spinodal decomposition
LiFePO4
lithium dynamics
Author
Peter Benedek
Swiss Federal Institute of Technology in Zürich (ETH)
Stanford University
Xueyan Zhao
Swiss Federal Institute of Technology in Zürich (ETH)
Emanuel Rudolf Bileter
Swiss Federal Laboratories for Materials Science and Technology (Empa)
Annina Moser
Swiss Federal Institute of Technology in Zürich (ETH)
Ola Kenji Forslund
Royal Institute of Technology (KTH)
Nami Matsubara
Royal Institute of Technology (KTH)
E. Nocerino
Royal Institute of Technology (KTH)
Stephen P. Cottrell
STFC Rutherford Appleton Laboratory
Marisa Medarde
Paul Scherrer Institut
Yasmine Sassa
Chalmers, Physics, Materials Physics
Ramesh Shunmugasundaram
Swiss Federal Institute of Technology in Zürich (ETH)
Thomas Francisco Jaramillo
Stanford Engineering
Stanford University
A. Borgschulte
Swiss Federal Laboratories for Materials Science and Technology (Empa)
Fanni Jurànyi
Laboratory for Neutron Scattering, Villigen
Martin Månsson
Royal Institute of Technology (KTH)
Vanessa Wood
Swiss Federal Institute of Technology in Zürich (ETH)
Matter
25902393 (ISSN) 25902385 (eISSN)
Vol. In PressSubject Categories (SSIF 2025)
Materials Chemistry
Condensed Matter Physics
Physical Chemistry
DOI
10.1016/j.matt.2026.102725