Hydrogen Bond-Enabled High-ICE Anode for Lithium-Ion Battery Using Carbonized Citric Acid-Coated Silicon Flake in PAA Binder

Abstract

A silicon-based lithium-ion battery (LIB) anode is extensively studied because of silicon’s abundance, high theoretical specific capacity (4200 mAh/g), and low operating potential versus lithium. Technical barriers to large-scale commercial applications include the low electrical conductivity and up to about 400% volume changes of silicon due to alloying with lithium. Maintaining the physical integrity of individual silicon particles and the anode structure is the top priority. We use strong hydrogen bonds between citric acid (CA) and silicon to firmly coat CA on silicon. Carbonized CA (CCA) enhances electrical conductivity of silicon. Polyacrylic acid (PAA) binder encapsulates silicon flakes by strong bonds formed by abundant COOH functional groups in PAA and on CCA. It results in excellent physical integrity of individual silicon particles and the whole anode. The silicon-based anode shows high initial coulombic efficiency, around 90%, and the capacity retention of 1479 mAh/g after 200 discharge–charge cycles at 1 A/g current. At 4 A/g, the capacity retention of 1053 mAh/g was achieved. A durable high-ICE silicon-based LIB anode capable of high discharge–charge current has been reported.

Tailoring Three-Dimensional Cross-Linked Networks Based on Water-Soluble Polymeric Materials for Stable Silicon Anode

“…The introduction of cross-linking within the linear framework is regarded as an effective route to withstand the huge volume change of Si particles. , By interconnecting polymer chains and creating a three-dimensional (3D) network with heightened mechanical robustness, the stresses caused by the considerable deformation of Si particles can be dissipated or dispersed through a multidimensional network. , Recently, small molecules such as citric acid (CA), boronic acid (BC), and glutaraldehyde (GA) have gained attention as straightforward and efficient cross-linking agents for establishing a moderate supramolecular network with precisely balanced covalent bonds. The formation of a covalent network between polymer skeletons enhances the mechanical strength of the polymer network, which increases the durability of the polymer binder.…”