The electrochemical behavior of poly 1-pyrenemethyl methacrylate binder and its effect on the interfacial chemistry of a silicon electrode

Abstract

The physico-chemical properties of poly (1-pyrenemethyl methacrylate) (PPy) are presented with respect to its use as a binder in a Si composite anode for Li-ion batteries. PPy thin-films on Si(100) wafer and Cu model electrodes are shown to exhibit superior adhesion as compared to conventional polyvinylidene difluoride (PVdF) binder. Electrochemical testing of the model bi-layer PPy/Si(100) electrodes in a standard organic carbonate electrolyte reveal higher electrolyte reduction current and an overall irreversible cathodic charge consumption during initial cycling versus the uncoated Si electrode. The PPy thin-film is also shown to impede lithiation of the underlying Si. XAS, AFM, TGA and ATR-FTIR analysis indicated that PPy binder is both chemically and electrochemically stable in the cycling potential range however significant swelling is observed due to a selective uptake of diethyl carbonate (DEC) from the electrolyte. The increased concentration of DEC and depletion of ethylene carbonate (EC) at the Si/PPy interface leads to continuous decomposition of the electrolyte and results in non-passivating behavior of the Si(100)/PPy electrode as compared to pristine silicon. Consequently, PPy binder improves the mechanical integrity of composite Si anodes but it influences mass transport at the Si(100)/ PPy interface and alters electrochemical response of silicon during cycling in an adverse manner.

Advanced Electrochemical Analysis for Energy Storage Interfaces

“…For example, an electrolyte decomposition product (LiF) was observed to be present in lesser quantities on the 110 face, when compared to the other crystalline faces. A similar study was performed at the Si (100) surface by Haregewoin et al, where they found the coverage of a 25 nm-thick binder has a selective influence of solvent transport properties, which alters the interfacial process formed at the Si surface . CV was also used to probe the electrochemical accessibility of surface-modified electrodes.…”

“…A similar study was performed at the Si (100) surface by Haregewoin et al, where they found the coverage of a 25 nm-thick binder has a selective influence of solvent transport properties, which alters the interfacial process formed at the Si surface. 33 CV was also used to probe the electrochemical accessibility of surface-modified electrodes. Nicolau et al demonstrated that alkylphosphonic acid selfassembled monolayers (SAMs) controlled the wettability of solvent at the LiMn 2 O 4 cathode surface, which influenced the molecule and ion mobility at the vicinity of the electrode.…”

Ending the Chase for a Perfect Binder: Role of Surface Chemistry Variation and its Influence on Silicon Anodes

“…during their slurry preparation . This same work showed zeta potential measurements (though the procedure was not reported which is important as the zeta potential measurements are sensitive to concentrations, salts, and equilibration time amongst others) . In the Delpuech et al .…”

“…There have been numerous studies reporting or exploring the role of the binder . Most of these studies focus on the use of a single binder with a single silicon source that then are subjected to different drying schemes, voltage ranges, cycle number, processing conditions . Others focus on the same base binder with chemical modifications to the backbone or chemical structure or ratio of components .…”

Research Progress on Coating Structure of Silicon Anode Materials for Lithium‐Ion Batteries

“…The conducting polymer polypyrrole has been widely used in energy storage devices such as batteries and supercapacitors, usually as a binder and conductive additive [176] . Studies have found that the polymer can form a conductive matrix that provides a conductive skeleton to the cell, and it can also be used as a host matrix to prevent large volume changes during charge/discharge cycles [177] .…”