科研之友
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摘要
LiNd (x) Mn2 -aEuro parts per thousand x O-4 samples are synthesized via co-precipitation technique. The activation energies computed from thermogravimetric analyses on the basis of Ozawa method have been observed to linearly increase with increase in dopant concentration. X-ray diffraction analyses indicate the cubic-spinel structure for all the samples. The lattice parameter has been observed to decrease with increasing concentration of Nd3 + doping. The octahedral site preference of neodymium dopant in the LiMn2O4 structure has been elucidated using XRD and FT-IR studies. The porosity and surface roughness obtained from SEM analysis have been observed to decrease with increase in Nd3 + dopant concentration in LiMn2O4 lattice. The electrochemical performances of the electrodes were analysed through cyclic voltammetry, chronopotentiometry and electrochemical impedance techniques. The specific capacity has been observed to decrease initially with increase in Nd3 + dopant concentration, whereas the capacity retention has increased with increase in dopant concentration. The observed percentage capacity retention after 50 cycles of the electrodes LiNd0 center dot 05Mn1 center dot 95O4, LiNd0 center dot 10Mn1 center dot 90O4 and LiNd0 center dot 15Mn1 center dot 85O4 were 88 center dot 4%, 97 center dot 1% and 96 center dot 8%, respectively. The Li ion diffusion coefficient ascertained using electrochemical impedance spectroscopy was found to be higher for LiNd0 center dot 10Mn1 center dot 90O4 around 3 center dot 74 x 10 (-aEuro parts per thousand 12) cm(2) s (-aEuro parts per thousand 1).
- 出版日期2012-6
