A Solution-Mediated Pathway for the Growth of the Solid Electrolyte Interphase in Lithium-Ion Batteries

摘要

Lithium-ion batteries (LIBs) are a widely used battery technology. During theinitial LIB cycle, a passivation layer, called the solid electrolyte interphase(SEI), forms on the anode surface, which plays a crucial role in the performanceand long-term cyclability of LIBs. The overall mesoscale mechanismsof SEI formation and its composition remain elusive both in experimental andcomputational approaches. Here a multiscale approach to comprehensivelycharacterize the growth and composition of the SEI based on a chemistryspecificreaction network is presented. Generating an ensemble of over 50 000simulations representing different reaction conditions, it is found that theorganic SEI forms and grows in a solution-mediated pathway by aggregationof SEI precursors far away from the surface via a nucleation process. Thesubsequent rapid growth of these nuclei leads to the formation of a porouslayer that eventually covers the surface. This finding offers a solution to theparadoxical situation that SEI constituents can form only near the surface, whereelectrons are available, but does not stop growing when this narrow region iscovered. The study is able to identify the key reaction parameters that determineSEI thickness, which pave the way to optimize battery performance and lifetime.