Lithium Substituted Poly(acrylic acid) as a Mechanically Robust Binder for Low-Cost Silicon Microparticle Electrodes

Abstract

Silicon microparticles (SiMPs) are attractive anode materials for lithium ion batteries due to their high theoretical capacity, low cost, high initial Coulombic efficiency, and large packaging density. However, the substantial volume change induced by lithiation/delithiation causes the pulverization and loss of electronic conductivity of SiMPs, which lead to the fast capacity fading. In this study, we report that the cycling stability of SiMP electrodes can be effectively improved by using environmentally friendly and cost-efficient lithium (Li) substituted poly(acrylic acid) (PAA-xLi, x ≤ 1) as binders. Noticeably, the SiMP/PAA-0.75Li electrode with a mass loading of ∼0.9 mg/cm 2 can deliver a significantly higher capacity (2125 mAh/g, 100 cycles) at C/3 (1200 mA/g) than that (730 mAh/g) made of the pristine PAA (i.e., PAA-0Li) binder. We focused on understanding the mechanism of PAA-xLi binders by correlating the mechanical properties of SiMP/PAA-xLi electrodes with their electrochemical stability. The effectiveness of PAA-0.75Li can be attributed to its high elasticity and strong adhesion with SiMPs, both of which greatly enhance the mechanical integrity of SiMP electrodes and help keep pulverized SiMPs coalesced during cycling. These findings offer important design principles of binders for low-cost SiMP electrodes.

A Comparative Investigation of Various Binders for Silicon Anodes: Interactions with Other Components, Rheological Property, and Behavior in Operando Dilatometry

“…However, the R ct for PVDF and PAN electrodes grow faster, indicating unstable interface and continuous growing SEI due to weak interaction between the binders and Si, which leads to an increase in the electrochemical reaction resistance. [ 51,54 ]…”

“…However, the R ct for PVDF and PAN electrodes grow faster, indicating unstable interface and continuous growing SEI due to weak interaction between the binders and Si, which leads to an increase in the electrochemical reaction resistance. [51,54] The infrared-attenuated total reflection (IR-ATR) spectra for electrodes with different binders before and after cycling are presented in Figure 8. Fresh Si-PVDF electrode is dominated by -CF 2 at 1172cm −1 .…”

Toward Superior Low-Temperature Performance and Safe Cathode Slurry Fabrication via 3-Methoxy-N,N-dimethylpropionamide as a Low-Toxicity and Facile Solvent

“…Lithium-ion batteries (LIBs) have been playing a vital role in various dimensions of human lives, such as electric vehicles, portable devices, and large-scale energy storage equipment, since their commercialization in 1990. − Despite persistent pursuits in optimizing the electrolyte formula, − electrode improvement, − and separator − materials to satisfy people’s demands on battery performances, slurry fabrication is the first and an essential step in the battery production process that greatly influences the battery quality. Currently, NMP is employed on a large scale to disperse the binder, conductive agent (CA), and active material (MA) to produce the cathode slurries. , However, NMP is subject to regulation in EU countries under REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals), which aims to promote the protection of human health and the environment from the risks posed by chemicals through the processes of registration, evaluation, authorization, restriction, classification, labeling, and packaging (CLP) regulations.…”

Impact of Binder Functional Groups on Controlling Chemical Reactions to Improve Stability of Rechargeable Zinc-Ion Batteries

“…If carefully chosen, the binder can help mitigate the abovementioned problems in the ZIB cathode at a lower cost. In Li batteries, binder selection has been shown to play an important role in improving the stability of electrodes and enhancing battery performance. − However, the role of binders in ZIBs has not been comprehensively investigated to date, and little research has been carried out in this area.…”