Study on Polymer Binders for High-Capacity SiO Negative Electrode of Li-Ion Batteries

Abstract

High-capacity SiO powder composite electrodes for rechargeable lithium-ion batteries are prepared with different polymer binders of poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), sodium carboxymethyl cellulose (CMCNa), and conventional poly(vinylidene fluoride) (PVdF). Electrode performance of the SiO composites highly depends on selection of binders, and their electrochemical reversibility is drastically improved by using PAA as the binder in comparison to the PVdF, CMCNa, and PVA binders. Coulombic efficiency at the initial cycle is improved for the SiOÀPAA composite electrode, and the reversible capacity reaches 700À750 mAh g À1 for continuous fifty cycling test at a rate of 100 mA g À1 . The improvement mechanism of SiOÀPAA composite electrode is characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, self-discharge test, and adhesive strength test. Amorphous PAA polymer not only tightly binds but also covers the individual SiO particles. Moreover, the PAA binder suppresses swelling of the composite electrode with the electrolyte solution compared to the PVdF binder. Through-thickness electric resistance of the PAA composite electrode is much lower than that of the PVdF when it is wet with the electrolyte. It is proposed that these characters of the PAA binder effectively suppress isolation of the SiO powders in the composite electrode associated with the large volume expansion/shrinkage during the lithiation/delithiation processes.

Nanocomposites of silicon and carbon derived from coal tar pitch: Cheap anode materials for lithium-ion batteries with long cycle life and enhanced capacity

“…Compared with conventional poly(vinylidene fluoride)(PVdF), the polymers with carboxy groups, such as polyacrylic acid (PAA) and carboxymethyl cellulose(CMC), can react with hydrocyl functionalities on the both carbon and silicon surfaces to confine the active material to the binder, which is responsible for the improvement of the electrode. [33][34] Remarkable progress has been made recently, alginate sodium (AS), a new kind of bio-derived binder with higher content of carboxylic group, can result in a large number of possible binder-Si / binder-C bonds and eventually much better cycling performance. [35] Here, we present a facile sintering method to synthesize Si/amorphous carbon (AC) composite materials, which is easy to be scaled up.…”

Catalytic Role of Ge in Highly Reversible GeO2/Ge/C Nanocomposite Anode Material for Lithium Batteries

“…Thus, much research has been focused on high capacity materials such as silicon (4200 mAh/g), [1][2][3][4][5][6] germanium (1623 mAh/g), [7][8][9][10][11][12][13] and tin (993 mAh/g) [14][15][16][17][18][19] to replace the graphite anode. The oxides of these metals (SiO, [20][21][22][23] Germanium dioxide nanoparticles have been previously studied as anode material for LIBs and were reported to react with up to 9 Li + during the first discharge cycle. 26 The lithium storage mechanism is described by an initial conversion reaction ( …”

Layered Oxide, Graphite and Silicon-Graphite Electrodes for Lithium-Ion Cells: Effect of Electrolyte Composition and Cycling Windows

“…polyvinylidene fluoride (PVDF). 6,8,10 Direct incorporation and mixing of silicon particles into standard graphite slurries also provides a means of incrementally improving electrode capacity, while retaining the higher durability of graphite electrodes. …”