High-Performance\nCarboxymethyl Cellulose Integrating\nPolydopamine Binder for Silicon Microparticle Anodes in Lithium-Ion\nBatteries

Abstract

Silicon\nmicroparticles (SiMPs) have been gradually explored as\nthe anode materials for lithium-ion batteries (LIBs) because they\nhave higher tap density and lower cost than nanostructured Si and\nthus are more suitable for commercial high-energy battery applications.\nDeveloping a binder to alleviate the volume effect of SiMPs and ensure\nelectrode stability during cycling is an effective method. Here, we\npropose a water-soluble binder by integrating carboxymethyl cellulose\n(CMC) with polydopamine (PDA) prepared from an alkaline aqueous solution,\nand the conventional buffer tris, an organic substance, is discarded\nto avoid problems during electrode preparation. The obtained binder\nCMC-10% PDA exhibits higher viscosity and better mechanical properties\nthan CMC due to the strong interaction between CMC and PDA through\nhydrogen bonds and some covalent bonds. The SiMP anodes with the binder\n(the Si@CMC-10% PDA electrodes) demonstrate excellent cycling stability\n(above 1700 mAh g^–1 at 0.2 C after 1000 cycles)\nand rate performance (1269 mAh g^–1 at 4 C) and can\ndeliver a high area capacity above 3 mAh cm^–2 at\na Si load of 1.36 mg cm^–2. The full cells composed\nof the Si@CMC-10% PDA anodes and lithium iron phosphate (LFP) cathodes\ncan maintain an 80% capacity retention after 50 cycles, demonstrating\npractical application potential.