Breaking the “dead Li” Barrier: A cross-stacked dual-function framework by SWNTs in graphite-Li hybrid anodes

Abstract

The accumulation of “dead Li” between lithiated graphite particles leads to interfacial failure, rapid capacity degradation, and reduced longevity in graphite-Li hybrid anodes. To address this issue, we developed a cross-stacked dual-function framework incorporating single-walled carbon nanotubes (SWNTs) that facilitates efficient electron/ion transmission and creates a quasi-three-dimensional porous structure. This framework establishes unobstructed pathways for electron and ion transport between graphite particles, overcoming transmission barriers caused by “dead Li” accumulation and side reactions. Additionally, the quasi-three-dimensional porous structure accommodates more “dead Li” minimizing its accumulation on graphite particles and preserving the activity of graphite intercalation compounds (GICs: LiC12, LiC6, etc.). The dual-function framework ensures excellent cycling performance, achieving 345 cycles at a lithiation level of 500 mAh·g−1 with an average Coulombic efficiency of 98.7 %. When paired with lithium iron phosphate (LFP) cathodes, the hybrid anode demonstrates remarkable capacity retention of 80 % over 300 cycles. This work presents an effective strategy for enhancing the performance of hybrid anodes through rational optimization of mesoscale interfacial transmission and electrode structure.