Carbon Nanocluster-Mediated Nanoblending Assembly for Binder-Free Energy Storage Electrodes with High Capacities and Enhanced Charge Transfer Kinetics

Abstract

The effective spatial distribution and arrangement of electrochemically active and conductive components within metal oxide nanoparticle (MO NP)-based electrodes significantly impact their energy storage performance. Unfortunately, conventional electrode preparation processes have much difficulty addressing this issue. Herein, this work demonstrates that a unique nanoblending assembly based on favorable and direct interfacial interactions between high-energy MO NPs and interface-modified carbon nanoclusters (CNs) notably enhances the capacities and charge transfer kinetics of binder-free electrodes in lithium-ion batteries (LIBs). For this study, carboxylic acid (COOH)-functionalized carbon nanoclusters (CCNs) are consecutively assembled with bulky ligand-stabilized MO NPs through ligand-exchange-induced multidentate binding between the COOH groups of CCNs and the surface of NPs. This nanoblending assembly homogeneously distributes conductive CCNs within densely packed MO NP arrays without insulating organics (i.e., polymeric binders and/or ligands) and prevents the aggregation/segregation of electrode components, thus markedly reducing contact resistance between neighboring NPs. Furthermore, when these CCN-mediated MO NP electrodes are formed on highly porous fibril-type current collectors (FCCs) for LIB electrodes, they deliver outstanding areal performance, which can be further improved through simple multistacking. The findings provide a basis for better understanding the relationship between interfacial interaction/structures and charge transfer processes and for developing high-performance energy storage electrodes.