Multifunctional Nano-Architecting of Si Electrode for High-Performance Lithium-Ion Battery Anode

Silicon (Si)-based anodes for lithium-ion batteries are highly attractive due to their high lithium storage capacity, but their performance is typically plagued by huge volumetric changes during battery cycling. Researchers have traditionally considered the roles of interactive binders and conductive additives as separate entities. Necessary additions of these two components often leads to significantly decreased mass ratio of Si to non-active material, which inevitably limits the anode's absolute capacity. To achieve a better utilization efficiency, a multifunctional composite binder was developed by cross-linking a poly(acrylic acid) (PAA) and carboxymethyl cellulose (CMC) spine with polyacrylonitrile (PAN) through a thermolysis induced nanoarchitecturing (TIN) process. The composite binder strongly interacts with Si, providing a sturdy structure with efficient pathways for both Li-ion and electron transport. The cross-linked carboxyl groups from PAA and CMC offered a robust 3D cross-linked network, anchoring SiO2 coated Si nanoparticles onto a highly-porous carbon scaffold, creating a stable solid electrolyte interphase. The composite anode not only exhibits a high initial capacity of 3472.6 mAh g(-1) with an initial Coulombic efficiency of 89.1%, but also provides excellent cycling stability for 650 cycles at a high current density of 3000 mA g(-1). (C) 2019 The Electrochemical Society.