Improved Electrochemical Performance of Modified Mesocarbon Microbeads for Lithium‐Ion Batteries Studied using Solid‐State Nuclear Magnetic Resonance Spectroscopy

Abstract

Lithium‐intercalating materials such as graphite are of great interest, especially for application in lithium‐ion batteries. In this work we present an investigation of the electrochemical performance of mesocarbon microbeads (MCMB) modified with copper to reveal the basic electrochemical mechanisms. Copper‐modified graphite is known to have better long‐term cycling behavior as well as higher capacity compared to the pristine material. Several reasons for these effects were postulated but not proven. Solid‐state nuclear magnetic resonance (NMR) spectroscopy provides structural and dynamic information on lithium in ionic conductors. To elucidate the changes in structure and dynamics for the pristine and the modified material, we have employed multi‐nuclear solid‐state NMR spectroscopy as well as 7Li spin‐lattice relaxation measurements and were able to clarify some reasons for the improved characteristics of copper‐modified graphite compared to the pristine material, which include increased solid–electrolyte interface (SEI) formation, a facilitated diffusion of lithium ions through the SEI, and reduced moisture.

Local Ion Dynamics in Polycrystalline β-LiGaO2: A Solid-State NMR Study

“…There are several reports on solid-state NMR studies of materials with fast diffusing Li ions [7][8][9][10][11]. Most of them focus on materials used in LIB's and investigate their dynamics, structure and conductivity behaviors.…”

Solid-State NMR to Study Translational Li Ion Dynamics in Solids with Low-Dimensional Diffusion Pathways

“…Bereitgestellt von | Technische Informationsbibliothek Hannover Angemeldet Heruntergeladen am | 13.11.17 10:34impedance studies dealing with practical aspects of graphite anode materials are, e.g. presented in Refs [59,60]…”