Keywords

polymeric binder, silicon anode, silicon active material, adhesion layer, Li-ion battery

Abstract

Polymer binders are crucial components in providing both mechanical support and chemical stability to the structure of porous Li-ion electrodes. Particularly in silicon anodes, the active material undergoes substantial volume expansion of up to 275%. Due to the mechanical constraint of the current collector, these silicon materials tend to expand in the normal direction while exhibiting substantial particle rearrangement and plastic deformation. Conventional rigid binders such as polyacrylic acid (PAA) and polyimide (PI), while providing satisfactory initial capacity, do not eliminate diminished long-term performance. Our research attempts to develop binder formulations that can accommodate sufficient flexibility for the substantial volume changes of silicon particles. Specifically, we explore the use of short-chain polymer binders and a strategic blend of binders with different molecular weights. Experiments have demonstrated that cells combining both long- and short-chain PAA binders delivered an initial capacity of 2200 mAh/g at a 0.1C rate, compared to 1700 mAh/g for pristine PAA cells. Initial work indicated that shorter polymer chains might compromise the adhesion to the current collector, so we developed a multilayer anode (MLA) structure to mitigate this issue. Nevertheless, at this early stage of development, there was no observed increase in cycling performance for the MLA electrodes.

Original Publication Citation

Sun, F., Zurita-Garcia, L., & Wheeler, D. R. (2025). Effect of Short-Chain Polymer Binders on the Mechanical and Electrochemical Performance of Silicon Anodes. Batteries, 11(9), 329. https://doi.org/10.3390/batteries11090329

Document Type

Peer-Reviewed Article

Publication Date

2025-09-01

Publisher

MDPI

Language

English

College

Ira A. Fulton College of Engineering

Department

Chemical Engineering

University Standing at Time of Publication

Full Professor

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