title: The Effects of Cross-Linking in a Supramolecular Binder on Cycle Life in Silicon Microparticle Anodes.
abstract: Self-healing supramolecular binder was previously found to enhance the cycling stability of micron-sized silicon particles used as the active material in lithium-ion battery anodes. In this study, we systematically control the density of cross-linking junctions in a modified supramolecular polymer binder in order to better understand how viscoelastic materials properties affect cycling stability. We found that binders with relaxation times on the order of 0.1 s gave the best cycling stability with 80% capacity maintained for over 175 cycles using large silicon particles (∼0.9 um). We attributed this to an improved balance between the viscoelastic stress relaxation in the binder and the stiffness needed to maintain mechanical integrity of the electrode. The more cross-linked binder showed markedly worse performance confirming the need for liquid-like flow in order for our self-healing polymer electrode concept to be effective.
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Lopez
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Andrews
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.|Stanford Institute for Materials and Energy Sciences , SLAC National Accelerator Laboratory, Menlo Park, California 94205, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Zhenan
authors.initials: Z
authors.lastname: Bao
keywords: high capacity anode; lithium-ion battery; microparticles; polymer binder; self-healing; silicon; viscoelasticity