A ureido-pyrimidinone (UPy)-functionalized poly(acrylic acid) grafted with poly(ethylene glycol)(PEG), designated PAU-g-PEG, was developed as a high performance polymer binder for Si anodes in lithium-ion batteries. By introducing both a ureido-pyrimidinone (UPy) unit, which is capable of self-healing through dynamic hydrogen bonding within molecules as well as with Si, and an ion-conducting PEG onto the side chain of the poly(acrylic acid), this water-based self-healable and conductive polymer binder can effectively accommodate the volume changes of Si, while maintaining electronic integrity, in an electrode during repeated charge/discharge cycles. The Si@PAU-g-PEG electrode retained a high capacity of 1,450.2 mAh g−1 and a Coulombic efficiency of 99.4% even after 350 cycles under a C-rate of 0.5 C. Under a high C-rate of 3 C, an outstanding capacity of 2,500 mAh g−1 was also achieved, thus demonstrating its potential for improving the electrochemical performance of Si anodes.
The large volume expansion of a silicon (Si) anode causes
severe
mechanical failure, limiting its use in lithium-ion batteries (LIBs).
Using functional polymers as a binder material is an approach to this
issue. We explore the applicability of the water-soluble natural polysaccharide
lambda carrageenan (CGN) as a binder for Si nanoparticles in LIBs.
The characteristic binder properties of commercial (CGN-com) and custom
(ext-CGN) CGNs are investigated. CGN binders exhibit excellent mechanical
characteristics, remarkable interfacial adhesion, and strong cohesion.
The high density of sulfonyl groups in CGN improves the lithium-ion
transport kinetics; CGN effectively buffers the volume expansion of
Si during alloying, enhancing cycling and rate performance. After
300 cycles at 0.5 C, the Si@CGN electrode delivers a reversible capacity
of 1623.75 mAh g–1 and a rate capability of 2143.72
mAh g–1 at 5 C. The electrochemical performance
of Si@CGN-ext is about 91% of that of Si@CGN-com. Under all test conditions,
both outperformed Si anodes made with traditional binders. When paired
with the commercial NCM811 cathode, full cells using Si@CGN-com and
Si@CGN-ext have capacities of 79.96 and 75.68 mAh g–1, respectively, and superior stability for 50 cycles. This study
reveals the potential of CGN as a low-cost, sustainable binder for
Si anodes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.