Surface film morphology (AFM) and chemical features (XPS) of cycled V2O5 thin films in lithium microbatteries

Abstract

a b s t r a c tSputtered vanadium pentoxide thin films have been used as positive electrode in lithium microbatteries and extensively studied after cycling over the 31st galvanostatic cycles by two complementary techniques, especially well-adapted for thin films analysis: X-ray photoelectron spectroscopy and atomic force microscopy. This study is mainly focussed on the characterization of the surface film (solid electrolyte interface-type) which is formed during subsequent discharges and charges and especially on its composition and its morphology that are changing during cycling. First, the growth of a surface layer between the positive electrode and the liquid electrolyte has been evidenced upon the discharge as well as its partial dissolution upon the charge. Secondly, the chemical and topographic changes of this interfacial layer at various stages of cycling are discussed in correlation with the evolution of the discharge capacity over cycles.

The formation and stability of the solid electrolyte interface on the graphite anode

“…An unfavorable formation temperature (a low of <À30 C and a high >60 C) can cause structural changes to the pores structure and create a number of defective sites in the SEI layer [88,92]. This creates species accumulation at these defective sites to increase the amounts of reduction products constituting the SEI layer [1,4]. A low temperature generally affects diffusivity of the limiting reacting species that may result in the formation of a thin and unstable SEI layer [92] and does not affect the irreversible capacity of the batteries at least for first few cycles (<100 cycles) compared to high formation temperature, while a denser SEI would be formed on the edge plane at high temperature for the graphite anode.…”

Flexible energy storage devices based on graphene paper

“…The target was prepared by cold pressing from a V 2 O 5 powder (99.99%, Kojundo Chem.) and sintering at 600 C in air for 6 h. 27 A Lambda Physik KrF excimer laser with a wavelength of 248 nm was used in the deposition. 28 The laser fluence and repetition rate were controlled at 2 J cm À2 and at 10 Hz, respectively.…”

Selective oxidation of H2S over V2O5 supported on CeO2-intercalated Laponite clay catalysts

“…6 and 7 respectively. For V 2p, a new peak that appeared at 516.8 eV corresponds to the V 4+ state 18,20,34 (the area percentage is about 40%). Meanwhile, no new peak can be detected for Ce 3d.…”