Electrochemical Performance of the LiNi1/3Co1/3Mn1/3O2 in Aqueous Electrolyte.

LiNi_1/3Co_1/3Mn_1/3O₂ with a well-ordered layered structure, which is confirmed by X-ray diffraction, was synthesized by the sol-gel method. The electrochemical performance of LiNi_1/3Co1/3Mn113O2 was investigated in a 2 M LiNO3 aqueous solution and in an organic solution. LiNi_1/3Co_1/3Mn_1/3O₂ showed a much better rate capability in the aqueous solution than in the organic solution; both charge and discharge processes were finished in a few seconds. The cycle performance of the LiNi_1/3Co_1/3Mn_1/3O₂ electrode with different charge/discharge rates from 80 to 200C was tested, and it exhibited good cycle performance in the aqueous solution with only 9.1% capacity loss after 1000 cycles at 80C (charge and discharge processes both within 20 s). The diffusion coefficients of lithium ion in the bulk of LiNi_1/3Co_1/3Mn_1/3O₂ in the aqueous and organic solutions were calculated to be 1.39 X 10-¹s and 1.51 X 10^-10 cm²/s, respectively, by slow scan cyclic voltammetry. The electrochemistry impedance spectrum indicates that R_et in the aqueous solution is less than I Ω, which is 1-2 magnitude lower than in the organic solution. The fast and stable interfacial charge transfer in the aqueous solution should lead to improved electrochemical performance. [ABSTRACT FROM AUTHOR]