Controllable Preparation of Hierarchically Charge‐Separated Interface to Effectively Promote the Desolvation and Kinetics of Lithium Ions

Abstract

Abstract Solid‐electrolyte interphase (SEI) is one of the key factors to determine the performance of batteries. Electrolyte additives enhance SEI performance for fast charging and long cycle life but introduce system‐level uncertainties, including cathode degradation, safety hazards, and cost escalation. In this study, we prepare a composite electrode (BPQDs/GDYNTs) featuring a charge‐separated interface structure to improve the SEI directly without auxiliary additives. The BPQDs/GDYNTs are comprised of graphdiyne tubes (GDYNTs) with black phosphorus quantum dots (BPQDs) distributed on the surface. The charge transfer between BPQDs and GDYNTs creates a charge‐separated interface, thereby enabling the efficient adsorption of lithium (Li) ions by the electron‐rich state of GDYNTs while promoting the adsorption of hexafluorophosphate anion (PF 6 − ) on the electron‐deficient state of BPQDs. That facilitates the in situ formation of a thin and inorganic‐rich SEI containing fluorine‐ and phosphorus‐based species, which significantly enhances both the desolvation of Li‐ions and their kinetics. When utilized as the anode of Li‐ion batteries, the BPQDs/GDYNTs electrode exhibits fast‐charging capability and remarkable longevity, demonstrating ultra‐stable cycling performance over 50 000 cycles at a high current density of 10 A g −1 with negligible capacity decay.