Open AccessHigh Porosity Single-Phase Silicon Negative Electrode Made with Phase-Inversion
Author(s) -
Niccolo Paulo Jimenez,
Michael P. Balogh,
Ion C. Halalay
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/abe3f1
Subject(s) - electrode , materials science , porosity , phase inversion , fabrication , electrochemistry , silicon , composite material , analytical chemistry (journal) , optoelectronics , chemistry , medicine , biochemistry , alternative medicine , pathology , chromatography , membrane
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//Ni 0.6 Co 0.2 Mn 0.2 O 2 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//Ni 0.6 Co 0.2 Mn 0.2 O 2 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 μ m. 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.