Lithium-ion batteries (LIBs) have matured as a technology and serve as power sources in a wide range of applications. Nonetheless, emerging applications, represented by electric vehicles, have been imposing ever-challenging criteria with regard to the key electrochemical properties. Low-resistance anodes are highly desired for high-power and supercharging capabilities of LIBs, and these properties are collectively determined by the electrolyte composition and electrode binder. Here, we report the use of glycerol as an additive to the conventional styrene-butadiene rubber/carboxymethyl cellulose (SBR/CMC) binder for graphite anodes with the aim of lowering the interfacial resistance and thus improving the operating capability at high C-rates. Glycerol, as a plasticizer, increases the interchain free volume in the binder network and also promotes the dissociation of lithium salt owing to its high dielectric constant, both of which jointly facilitate lithium ion diffusion at the anode interface. As a result, the addition of a small amount (0.18 wt% of the entire electrode) of glycerol enhances the high-rate capability (i.e., >1 C). This study highlights the usefulness of small molecules as binder additives for improving the key performance parameters of LIBs without sacrificing other critical properties.

Maximizing the energy density of a lithium-ion battery cell by increasing the silicon content in the silicon-graphite (Si-Gr) composite anode is an ongoing research topic that is receiving much attention. However, the paradoxical surface characteristics of Si and Gr make it challenging to uniformly distribute the electrode components and maintain their adhesion during cycling accompanied with the immense volume change of Si. Here, an amphiphilic, tightly interlocked host-guest complex binder composed of pyrene-conjugated poly(acrylic acid) (Py-PAA) and a hyperbranched gamma-cyclodextrin polymer (gamma CDp) is reported. The pyrene unit of Py-PAA not only endows enhanced affinity to the Gr surface but also serves as a guest molecule capable of interlocking with the gamma CDp host. This highly effective host-guest interaction sustains the integrity of the electrode to enable superior cycling performance and rate capability for Si-Gr electrodes with commercial-level areal capacity. This study shows that hierarchical, multifunctional supramolecular binders of two kinds can offer improved battery performance for emerging high-capacity electrodes consisting of components with different surface characteristics compared to conventional binders of a single kind.

Sulfated-zirconia superacid enhances the performance of lithium-metal battery markedly by increasing the lithium-ion transference number and modifying the interfacial composition.

Recent research has built a consensus that the binder plays a key role in the performance of high-capacity silicon anodes in lithium-ion batteries. These anodes necessitate the use of a binder to maintain the electrode integrity during the immense volume change of silicon during cycling. Here, Zn2+-imidazole coordination crosslinks that are formed to carboxymethyl cellulose backbones in situ during electrode fabrication are reported. The recoverable nature of Zn2+-imidazole coordination bonds and the flexibility of the poly(ethylene glycol) chains are jointly responsible for the high elasticity of the binder network. The high elasticity tightens interparticle contacts and sustains the electrode integrity, both of which are beneficial for long-term cyclability. These electrodes, with their commercial levels of areal capacities, exhibit superior cycle life in full-cells paired with LiNi0.8Co0.15Al0.05O2 cathodes. The present study underlines the importance of highly reversible metal ion-ligand coordination chemistries for binders intended for high capacity alloying-based electrodes.