Electrochimica Acta An experimental and theoretical approach on the effect of presence of oxygen in milled graphite as lithium storage material

C.B. ROBLEDO; J.E. THOMAS; G. LUQUE; E.P.M. LEIVA; O. CÁMARA; D. BARRACO; A. VISINTIN

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2014 vol. 140 p. 160 - 167

0013-4686

tThe effect of milling time on the morphology of graphite is characterized by XRD, SEM, BET, FTIR andXPS and the electrochemical response of the resulting materials upon lithium-ion absorption is analyzedusing different techniques. As milling time is increased, the particle size diminishes and the amountof oxygen content increases. Concomitantly, the capacity for lithium adsorption also increases becausenew adsorption sites become available due to more surface area and oxygen functional groups. Theseeffects are interpreted using first-principles calculations, which show that the presence of oxygenatedspecies promotes lithium adsorption at higher potentials. This capacity increase is probably not relevantfor lithium-ion batteries since there is no intercalation process but rather an adsorption one, but may beof interest for supercapacitive applications. Diffusion coefficients of lithium for different graphite particlesizes are evaluated. The effects of diffusion, particle size and oxygen content are discussed.