Unveiling the dimensionality effect of conductive fillers in thick battery electrodes for high-energy storage systems

The applications of lithium-ion batteries are limited, as they cannot fulfill the requirements for high power output and reversible energy storage. The main challenges are centered around developing electrode architectures to produce both high energy and power. As one of the key components, conductive fillers play a vital role in battery electrodes, contributing to the electrical conductivity and shaping electrode structures, which significantly determine the rate capability. In this study, the dimensionality effect of conductive fillers on electrochemical performance is elucidated in thick electrodes for scalable energy storage. In particular, three types of conductive fillers: single-walled carbon nanotubes, graphene nanosheets, and Super P, are studied using commercial LiNi1/3Co1/3Mn1/3O2 as the model material. The role of these conductive fillers on electrode morphology, electrical percolation, and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 electrodes is comparatively investigated. Notably, electrodes with single-walled carbon nanotubes exhibit superior rate performance owing to both high electrical conductivity and tight wrapping architecture, which was further revealed by various advanced structural and electrochemical characterization. This work demonstrates the dimensionality effect of conductive fillers on both electrochemistry and electrode architecture and highlights the advantages of 1D conductive filler in thick electrodes, which brings new insights in future high energy/power systems.