Effect of Binder Architecture on the Performance of Silicon/Graphite Composite Anodes for Lithium Ion Batteries

Abstract

Although significant progress has been made in improving cycling performance of silicon-based electrodes, few studies have been performed on the architecture effect on polymer binder performance for lithium-ion batteries. A systematic study on the relationship between polymer architectures and binder performance is especially useful in designing synthetic polymer binders. Herein, a graft block copolymer with readily tunable architecture parameters is synthesized and tested as the polymer binder for the high-mass loading silicon (15 wt %)/graphite (73 wt %) composite electrode (active materials >2.5 mg/cm). With the same chemical composition and functional group ratio, the graft block copolymer reveals improved cycling performance in both capacity retention (495 mAh/g vs 356 mAh/g at 100th cycle) and Coulombic efficiency (90.3% vs 88.1% at first cycle) than the physical mixing of glycol chitosan (GC) and lithium polyacrylate (LiPAA). Galvanostatic results also demonstrate the significant impacts of different architecture parameters of graft copolymers, including grafting density and side chain length, on their ultimate binder performance. By simply changing the side chain length of GC-g-LiPAA, the retaining delithiation capacity after 100 cycles varies from 347 mAh/g to 495 mAh/g.

Conjugation with carbon nanotubes improves the performance of mesoporous silicon as Li-ion battery anode

“…The well-known drawbacks with silicon itself are the huge volumetric changes upon the lithiation and delithiation processes, and the subsequent loss of electrical contact during the delithiation phase as the material collapses 6 . New binders, binder architectures and electrolyte additives are being studied to mitigate this obstacle [7][8][9] . The current approaches to overcome the issue with silicon are typically based on different nanomaterials like nanoparticles, nanowires and thin films [10][11][12] .…”

Sustainable Battery Materials from Biomass

“…In addition to the carboxylate functionality, amine functionalities may also support binding properties. Furthermore, functionalized chitosan‐based binders with different carboxylate or amide side chains were introduced. Crosslinking of chitosan chains was shown to increase stability, and grafting natural rubber as side chains helped to increase flexibility …”

Silicon Anodes for High‐Performance Storage Devices: Structural Design, Material Compounding, Advances in Electrolytes and Binders

“…Polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN) blend polymers and high‐stretching polyacrylamide (c‐PAM) binders all have excellent adhesion to silicon anodes (reversible capacity of 2736 mAh g −1 after 600 cycles at a current density of 3 A g −1 and 753 mAh g −1 at current density of 0.2 C) . Conjugated polymers comprising of cyclopentadithiophene and dimethyl terephthalate or terephthalic acid, the graft copolymer GC‐g‐LiPAA with GC as backbone and LiPAA as side chains or catechol‐functionalized chitosan cross‐linked by glutaraldehyde (CS‐CG+GA) both have high mechanical strength and adhesion, and they show extremely great potential in silicon‐based lithium‐ion battery applications . In addition, a new type of stretchable conductive adhesive (CG) polymer binder which is used as a binder for Si‐CG anodes and with extremely high reversible capacity (after 700 cycles at a current density of 840 mA g −1 , a large reversible capacity remains at 1500 mAh g −1 ) .…”