Effect of synthesis condition on the structural and electrochemical properties of Li[Ni_(1/3) Mn_(1/3) Co_(1/3)] O_2 prepared by carbonate co-precipitation method

摘要

In order to get homogeneous layered oxide Li[Ni_(1/3) Mn_(1/3) Co_(1/3)] O_2 as a lithium insertion positive electrode material, we applied carbonate co-precipitation. The oxide compounds were synthesized under different annealing temperature. XRD experiment revealed that the layered Li[Ni_(1/3) Mn_(1/3) Co_(1/3)] O_2 material can be synthesized at lower temperature of 750 deg C, and the oxidation state of Ni, Mn and Co in the cathode confirmed by XPS were 2+, 4+ and 3+, respectively. SEM observation shows that the synthesized materials have spherical particle morphology and the morphology could be controlled by carbonate co-precipitation method. The cathode synthesized at 800 deg C showed small irreversible capacity loss of 10.72 percent and high discharge capacity of 186.7 mAh g~(-1) as well as stable cycling performance in the voltage range 2.8-4.5 V_(Li/Li~+). In spite of difference in specific surface area, rate capability of the samples synthesized in the temperature range 750-900 deg C showed similar rate capability and all these cathodes delivered high discharge capacity of over than 143 mAhg~(-1) at 2.5 C (450 mA g~(-1)).