Abstract
Herein we present a Si electrode fabrication process that includes a phase-inversion step subsequent to slurry-based electrode casting and discuss its consequences for Si//Ni0.6Co0.2Mn0.2O2 cell performance. The phase inversion consists of extracting 1-methyl-2-pyrrolidinone with water and the concomitant coagulation of the polyacrylonitrile binder. Phase inversion improves capacity retention by 50% during C/5 cycling of Si//Ni0.6Co0.2Mn0.2O2 coin cells between 3.0 and 4.2 V. Phase-inversion Si electrodes have (1) 80% porosity compared to 55% for standard electrodes; and (2) bimodal pore size distribution, consisting of micropores (as in standard electrodes) and macropores with dimensions of 2 to 20 μm. The surface film mass growth rate in phase-inversion electrodes is smaller by 24% than in air-dried Si electrodes. Furthermore, during electrochemical cycling, the overall thickness change rate in phase-inversion electrodes is 5x smaller than in air-dried electrodes. Additionally, the high porosity electrodes display a reduced tendency to deform during electrochemical cycling. The insertion of a phase-inversion step into the electrode fabrication process may thus mitigate the volume expansion of the cell, enabling efficient module and pack design, while also increasing battery durability.
Publisher
The Electrochemical Society
Subject
Materials Chemistry,Electrochemistry,Surfaces, Coatings and Films,Condensed Matter Physics,Renewable Energy, Sustainability and the Environment,Electronic, Optical and Magnetic Materials
Cited by
1 articles.
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