Nanoporous cuprous oxide/lithia composite anode with capacity increasing characteristic and high rate capability

摘要

Reticular nanoporous thin films of Cu2O-Li2O ( Cu: Li = 1:1) composite electrodes supported on nickel foam and copper foil substrates were prepared under optimized conditions at 250 degrees C by the electrostatic spray deposition ( ESD) technique. X-ray diffraction ( XRD) and x-ray photoelectron spectroscopy ( XPS) indicate that the as-deposited films are composed of Cu2O and Li2O. It is found that such a film as an electrode in lithium cells exhibits abnormal characteristics of strong and continuous capacity rise ( up to 0.81% per cycle) and outstanding rate capability. Even before a long-time cycling, the specific capacity at 1, 5, 10 and 15 C is 400, 320, 310 and 305 mA h g(-1) for the Cu2O-Li2O film supported on nickel foam substrate. XPS analysis and AC impedance spectroscopy suggest two mechanisms, i.e. valence-related capacity rise and surface-related capacity rise. These composite films may be useful in high power and high energy density lithium-ion batteries.