Local structure of ball-milled carbons for lithium ion batteries: a pair distribution function analysis

摘要

The local atomic structure of ball-milled carbons was investigated by radial distribution function (RDF) analysis using pulsed time-of-flight neutron diffraction. The results ehibit a gradual loss of long-range order as a function of milling time. Modeling of the elastic structure factors and of the differrential correlation functions identified the structure of ball-milled carbons as finite-size graphene fragments whose size decreases continuously with milling time. The large increases in lithium reversible capacity after 20 hours of milling was correlated with the loss of interlayer correlation between graphite flakes, similar to the structure of hard carbons in the "House of Cards" model.