Raman spectroscopic determination of phase evolutions in LiAl_xCo_1-xO_2 battery materials

摘要

Superior battery materials LiAl_xCo_1-xO_2(x=0.0, 0.1, 0.3, 0.5, and 0.7) were synthesized using a solution-based route at various sintering temperatures (450-800deg.C). In this communication, we report on the use of Raman spectroscopy to study effect of composition and sintering temperature on the resulting material. The phase evolutions in LiAl_xCo_1-xO_2 compositions were studied using micro-Raman phase evolutions in LiAl_xCo_1-Xo_2 compositions were studied using micro-Raman spectroscopy and a phase diagram is proposed based on the observations. For less Al content, the low-temperature phases of LiAl_xCo_1-xO_2 showed Raman spectra Corresponding to a monoclinic (space group C2/m) structure, while a low-temperature Spinel (space group Fd3m) phase was observed for 50/100 or more Al in these Compounds. All these compositions exhibited a layered hexagonal (space group R3m) Structure when sintered above 700deg.C. Raman spectra also revealed residual Co_3O_4 in The low-temperature forms of LiCoO_2 and LiAl_0.01Co_0.9O_2.