Nano-spinel Li x Mn 2 O 4 (0.6≤x≤1.0)was synthesized by two steps of copre cipitation and calcination.The influences of calcination temperature,time and Li /Mn ratio on the crystal structure and the particle size of...Nano-spinel Li x Mn 2 O 4 (0.6≤x≤1.0)was synthesized by two steps of copre cipitation and calcination.The influences of calcination temperature,time and Li /Mn ratio on the crystal structure and the particle size of Li x Mn 2 O 4 were investigated.It was shown that the higher the calcination temperature,the more complete the crystal structure,and the larger the partic le size.Moreover,the influence of c alcination time on the crystal structure was insignificant when it was more than 3h at 700℃.With the increase of x in Li x Mn 2 O 4 in the range of 0.6～1.0,the d 111 and lattice parameter a increased fi rst and then decreased.The electrochemical properties of nano-spinel LiMn 2 O 4 using as cathode material of lithium-ion battery were studied.The low di scharge capacity might be due to the irreversible capacity loss brou ght by the large surface area and latt ice vacancies of the nano-spinel.展开更多
LiCoO2 precursors of the cathode material for lithium ion batteries were prepared from lithium hydroxide, basic cobalt carbonate and citric acid by a sol gel method. The LiCoO2 samples were obtained by sintering the g...LiCoO2 precursors of the cathode material for lithium ion batteries were prepared from lithium hydroxide, basic cobalt carbonate and citric acid by a sol gel method. The LiCoO2 samples were obtained by sintering the gel precursors at different temperatures and for different times. The thermal decomposition behavior of the gel precursors was examined by means of thermo gravimetric analysis and differential thermal analysis using a PCT IA thermal analyzer system. Their structures and morphologies were characterized by powder XRD and SEM techniques. It was found that using citric acid realized that the formation of LiCoO2 crystal can be clearly differentiated to the nucleation and growth processes of the crystals; furthermore, the crystal size can be controlled. Electrochemical tests using the LAND BT1 10 test system showed the electrochemical performance of the material is affected by its integrity and stability.展开更多
文摘Nano-spinel Li x Mn 2 O 4 (0.6≤x≤1.0)was synthesized by two steps of copre cipitation and calcination.The influences of calcination temperature,time and Li /Mn ratio on the crystal structure and the particle size of Li x Mn 2 O 4 were investigated.It was shown that the higher the calcination temperature,the more complete the crystal structure,and the larger the partic le size.Moreover,the influence of c alcination time on the crystal structure was insignificant when it was more than 3h at 700℃.With the increase of x in Li x Mn 2 O 4 in the range of 0.6～1.0,the d 111 and lattice parameter a increased fi rst and then decreased.The electrochemical properties of nano-spinel LiMn 2 O 4 using as cathode material of lithium-ion battery were studied.The low di scharge capacity might be due to the irreversible capacity loss brou ght by the large surface area and latt ice vacancies of the nano-spinel.
文摘LiCoO2 precursors of the cathode material for lithium ion batteries were prepared from lithium hydroxide, basic cobalt carbonate and citric acid by a sol gel method. The LiCoO2 samples were obtained by sintering the gel precursors at different temperatures and for different times. The thermal decomposition behavior of the gel precursors was examined by means of thermo gravimetric analysis and differential thermal analysis using a PCT IA thermal analyzer system. Their structures and morphologies were characterized by powder XRD and SEM techniques. It was found that using citric acid realized that the formation of LiCoO2 crystal can be clearly differentiated to the nucleation and growth processes of the crystals; furthermore, the crystal size can be controlled. Electrochemical tests using the LAND BT1 10 test system showed the electrochemical performance of the material is affected by its integrity and stability.
