Tannic Acid as a Small-Molecule Binder for Silicon Anodes

Abstract

Increasing demand for portable electronic devices, electric vehicles, and grid scale energy storage has spurred interest in developing high-capacity rechargeable lithium-ion batteries (LIBs). Silicon is an abundantly available anode material that has a theoretical gravimetric capacity of 3579 mAh/g and a low operating potential of 0–1 V vs Li/Li+. However, silicon suffers from large volume variation (>300%) during lithiation and delithiation that leads to pulverization, causing delamination from the current collector and battery failure. These issues may be improved by using a binder that hydrogen bonds with the silicon nanoparticle surface. Here, we demonstrate the use of tannic acid, a natural polyphenol, as a binder for silicon anodes in lithium-ion batteries. Whereas the vast majority of silicon anode binders are high molecular weight polymers, tannic acid is explored here as a small molecule binder with abundant hydroxyl (−OH) groups (14.8 mmol of OH/g of tannic acid). This allows for the specific evaluation of hydrogen-bonding interactions toward effective binder performance without the consideration of particle bridging that occurs otherwise with high molecular weight polymers. The resultant silicon electrodes demonstrated a capacity of 850 mAh/g for 200 cycles and a higher capacity when compared to electrodes fabricated by using high molecular weight polymers such as poly(acrylic acid), sodium alginate, and poly(vinylidene fluoride). This work demonstrates that a small molecule with high hydrogen-bonding capability can be used a binder and provides insights into the behavior of small molecule binders for silicon anodes.

Description
Advisor
Degree
Type
Journal article
Keywords
Citation

Sarang, Kasturi T., Li, Xiaoyi, Miranda, Andrea, et al.. "Tannic Acid as a Small-Molecule Binder for Silicon Anodes." ACS Applied Energy Materials, 3, no. 7 (2020) American Chemical Society: 6985-6994. https://doi.org/10.1021/acsaem.0c01051.

Has part(s)
Forms part of
Rights
This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society
Link to license
Citable link to this page