Toward an Ideal Polymer Binder Design for High-Capacity Battery Anodes

Abstract

The dilemma of employing high-capacity battery materials and maintaining the electronic and mechanical integrity of electrodes demands novel designs of binder systems. Here, we developed a binder polymer with multi-functionality to maintain high electronic conductivity, mechanical adhesion, ductility, and electrolyte uptake. These critical properties are achieved by designing polymers with proper functional groups. Through synthesis, spectroscopy and simulation, electronic conductivity is optimized by tailoring the key electronic state, which is not disturbed by further modifications of side chains. This fundamental allows separated optimization of the mechanical and swelling properties without detrimental effect on electronic property. Remaining electrically conductive, the enhanced polarity of the polymer greatly improves the adhesion, ductility, and more importantly, the electrolyte uptake to the levels of those available only in non-conductive binders before. We also demonstrate directly the performance of the developed conductive binder by achieving full-capacity cycling of silicon particles without using any conductive additive.3

Nanostructured conductive polymers for advanced energy storage

“…8b: (1) good electronic conductivity inherited from the conducive polymer framework, (2) good mechanical adhesion and ductility with tolerance of large volume changes, and (3) good electrolyte uptake to warrant high ionic conductivity. 49 Recently, a dynamic three-phase interline electropolymerization (D3PIE) method has been used to synthesize a freestanding PEDOT film which supports LiFePO 4 particles and acts as the cathode material for batteries (Fig. 9a).…”

“…Based on the designed electronic and mechanical properties, the tailored polymer binder achieves both high conductivity for electron conduction and mechanical integrity, resulting in high specific capacity and stable cycling performance. In their following work, 49 other functional groups were introduced into polyfluorene type conductive polymers. The designed PFEM-Si electrodes achieved full-capacity cycling of Si with excellent rate performance.…”

Recent Progress on Polymeric Binders for Silicon Anodes in Lithium-Ion Batteries

“…Chemical structures of the PVDF, PAA-Na, and CMC-Na binders [35]. ible tolerance against large volume changes, as well as good compatibility with the electrolyte solution for high-capacity metallic anodes [37]. Fig.…”

Dry-air-stable lithium silicide–lithium oxide core–shell nanoparticles as high-capacity prelithiation reagents

“…For example, Si is a particularly attractive anode material, owing to its high specific capacity of B4,200 mAh g À 1 , excellent material abundance and well-developed industrial infrastructure for manufacturing 16,18 . In the past several years, there has been exciting progress in addressing the issues associated with large volume change (4300%) during lithium insertion and extraction by designing nanostructured Si including nanowires and coreshell nanowires [19][20][21][22] , hollow particles and tubes [23][24][25] , porous materials 26,27 , Si/C nanocomposites [28][29][30] and by using novel binders [31][32][33][34] . One of the remaining issues for Si anodes is the large capacity loss in the first cycle.…”