Three‐Dimensional Holey Graphene Enwrapped Li₃V₂(PO₄)₃/N‐Doped Carbon Cathode for High‐Rate and Long‐Life Li‐Ion Batteries

Abstract

is a promising cathode material for highpower Li-ion batteries. Herein, a three-dimensional holey graphene enwrapped Li 3 V 2 (PO 4 ) 3 /N-doped carbon (LVPNCHG) nanocomposite has been successfully synthesized. The holes could be in-situ and directly introduced in graphene through H 2 O 2 chemical etching in the synthesis process, which could remarkably enhance the ion and electron transport and greatly improve the electrochemical performance of the LVPNCHG electrode: 78 mAh g À 1 at 150 C, 86.1 % capacity retention over 2000 cycles at 10 C, and 96 % capacity retention over 500 cycles at 1 C under À 20 °C. Moreover, in-situ distribution of relaxation time analysis was used to study LVPNCHG cathode during charge/discharge at 3.0-4.8 V, combined with in-situ X-ray diffraction measurement, and the results showed that a twophase reaction mechanism was involved during the insertion of Li + in the discharge process. Further demonstration of graphite//LVPNCHG full cell indicated great potential of the assynthesized materials for practical application.

Regulating Polysulfide Transformation and Deposition Kinetics in Lithium–Sulfur Batteries Based on 3D Conductive Framework

“…However, this rough description does not provide a detailed analysis of the complex electrochemical process. With DRT analysis, 30,53,54 the overlapping relaxation process can be decomposed into a series of local maxima, each representing an electrochemical process, which helps solve the subtle changes in EIS data. 53 Time constant τ and the peak area corresponding to different electrode polarization processes and polarization resistance (R p ), respectively.…”