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Layered LiCoO_2(HT-LiCoO_2)films were grown on Pt-metalized silicon(PMS)substrates and polished bulk nickel(PBN)substrates by pulsed laser deposition.The effects of substrate temperature,oxygen pressure,and substrate surface roughness on the microstructure of LiCoO2 films were investigated.It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO_2 films.The HT-LiCoO_2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains,whereas on PMS substrate,it is made up of loosely packed highly[001]preferential orientated triangular shaped grains with the average grain size less than 100 nm.Electrochemical measurements show that the highly[001]preferentially orientated nanostructured HT-LiCoO_2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45μA·h·cm~(-2)·μm~(-1)with a cycling efficiency of above 99% at the charge/discharge rate of 0.5 C.
Layered LiCoO_2 (HT-LiCoO_2) films were grown on Pt-metalized silicon (PMS) substrates and polished bulk nickel (PBN) substrates by pulsed laser deposition.The effects of substrate temperature, oxygen pressure, and substrate surface roughness on the microstructure of LiCoO 2 films were investigated. It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO 2 films. The HT-LiCoO 2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains , on on PMS substrate, it is made up of loosely packed highly [001] preferential orientated triangular shaped grains with the average grain size less than 100 nm. Electrochemical measurements show that the highly [001] preferentially orientated nanostructured HT-LiCoO_2 thin film grown on PMS substrate has good structural stability upon lithium insertion / extraction and can deliver an initial discharge capacity of approximately 45 μA · h · Cm -2 (μm) · μm -1 with a cycling efficiency of above 99% at the charge / discharge rate of 0.5 ° C.