Three-Dimensional Conductive Gel Network as an Effective Binder for High-Performance Si Electrodes in Lithium-Ion Batteries

Abstract

Silicon (Si) has been widely investigated as a candidate for lithium-ion batteries (LIBs) due to its extremely high specific capacity. The binders play a key role in fabricating high-performance Si electrodes which usually suffer from the huge volume expansion associated with the alloying and dealloying processes. Here we develop a facile route to prepare a three-dimensional (3D) conductive interpenetrated gel network as a novel binder for high-performance Si anodes through chemically cross-linking of acrylic acid monomer followed by the in situ polymerization of aniline. The excellent electrical conductivity, strong mechanical adhesion and high electrolyte uptake render the conductive gel network a potential binder for high-performance Si anodes. The resultant Si anodes exhibit excellent cycling stability, high Coulombic efficiency and superior rate capability, revealing better electrochemical properties compared to the Si anodes with conventional binders. The 3D conductive gel binder could not only accommodate the volume expansion and maintain electric connectivity, but also assist in the formation of stable solid electrolyte interphase (SEI) films. Such a strategy sheds light on the design of polymer binders in LIBs, especially for high-capacity electrode materials with huge volume changes during long-term cycling.

Polymer Binders Constructed through Dynamic Noncovalent Bonds for High‐Capacity Silicon‐Based Anodes

“…Yu et al presented a3 Dc onductive PAA/PANI interpenetrating polymer network (IPN) by in situ polymerization of aniline (ANI) monomers in the PAA-based hydrogels. [56] As shown in Figure 16, the strong hydrogen bonding between PAAa nd PANI was revealed by the FTIR spectrum peak at 1472 cm À1 , and electrostatic interactions were also formed between the protonated amine groups in PANI and-COO À in PAA. Both the intermolecular hydrogen bonding and ionic bondingcontributed to the stable conductive network, resulting in the Si-based electrode with PAA/PANI reaching ah igh ICE of 89.3 %a nd a high retention capacity of 2205 mAh g À1 after 300 cycles at a current density of 2400 mA g À1 .…”

“…[56] b) FTIR spectraofS i, Si-PAA/PANI, PAA/PANI, and PAA. [56] Chem.E ur.J. 2019, 25,10976 -10994 www.chemeurj.org 2019 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim voltage windowsa re usually pretty narrow.T he full cells with lithium iron phosphate (LiFePO 4 ), especially lithium nickel-manganese-cobalt oxide (NMC), as the cathodes always require high voltage stability.…”

Waterborne polyurethane as a carbon coating for micrometre-sized silicon-based lithium-ion battery anode material

“…Silicon (Si) has received increasing attention as a new negative electrode material with high theoretical capacity (3579 mA h g −1 ) [ 8 ]. Also, silicon has a relatively low voltage plateau, and is non-toxic, inexpensive and abundantly available in nature [ 9 – 11 ].…”

Kinetics and electrochemical evolution of binary silicon–polymer systems for lithium ion batteries

“…Hybridized networks and calcium-mediated cross-linked alginate binders have been used as novel gels for Si slurry. 17 Self-healing polymers via supramolecular interactions have been proposed for Si binders. 18 Wang et al reported a superabsorbent PAA-PVA gel for Si anodes, which effectively accommodated the volume change due to the adhesively transformable polymer network.…”