Tailoring Graphite Interlayers with Electron-Acceptor Bridges Raises Ion Diffusion Kinetics for Ultrafast Charging Batteries.

Abstract

Sluggish solid-state diffusion kinetics of lithium ions is among the primary bottlenecks limiting the fast-charging performance of graphite anodes. Pre-intercalating molecules in graphite interlayers can tune the valence π-electrons, but there are few systematic studies in designing such structures by electron coupling to optimize the charge transfer kinetics. Herein, deliberately guided by simulations, the present study identifies and develops a class of electron-acceptor aluminum chloride species for intercalation into graphite (AC-G), aiming to accelerate lithium ions charge transfer to the intercalated graphite through the formation of electron-acceptor bridges within the graphite interlayers. Consequently, the AC-G achieves a two-order-of-magnitude enhancement in lithium ions diffusion coefficient (5.85 × 10^-7 cm² s^-1) compared to that in pristine graphite. It delivers stable cycling over 2000 cycles with a high areal capacity retention of 3.84 mAh cm^-2 at 1C and maintains 500-cycle stability at 5C. Furthermore, an Ah-level pouch cell assembled with AC-G and cathode achieves an energy density of 285 Wh kg^-1 at 3C. The present work provides a new design strategy for graphite by introducing interlayer electron-bridging structures, offering valuable insights for next-generation fast-charging lithium-ion batteries.