High-capacity Li[Ni0.8Co0.06Mn0.14]O2 positive electrode with a dual concentration gradient for next-generation lithium-ion batteries
K.J. Park, B.B. Lim, M.H. Choi, H.G. Jung, Y.K. Sun, M. Haro, N. Vicente, J. Bisquert, G. Garcia-Belmonte J. Mater. Chem. A, 3, 22183-22190
To increase the reversible capacity of layered lithium nickel-cobalt-manganese oxide, a Li [Ni0.8Co0.06Mn0.14]O2 positive electrode with a two-sloped full concentration gradient (TSFCG) was successfully synthesized via co-precipitation. The TSFCG maximizes the Ni concentration in the particle core and the Mn concentration on the particle surface. The TSFCG Li[Ni0.8Co0.06Mn0.14]O2 positive electrode showed improved overall electrochemical properties (i.e., reversible capacity, cycle life, and rate capability) and thermal stability compared to a conventional positive electrode (CC) Li [Ni0.8Co0.06Mn0.14]O2 without a concentration gradient. Electrochemical impedance spectroscopy showed that the high stability of the outer surface composition of Li[Ni0.64Co0.06Mn0.30]O2 is responsible for reduction in surface resistance and charge transfer resistance by decreasing the parasitic reaction with the electrolyte. These reduced resistances explain the superior rate capability of TSFCG positive electrodes.
To increase the reversible capacity of layered lithium nickel-cobalt-manganese oxide, a Li [Ni0.8Co0.06Mn0.14]O2 positive electrode with a two-sloped full concentration gradient (TSFCG) was successfully synthesized via co-precipitation. The TSFCG maximizes the Ni concentration in the particle core and the Mn concentration on the particle surface. The TSFCG Li[Ni0.8Co0.06Mn0.14]O2 positive electrode showed improved overall electrochemical properties (i.e., reversible capacity, cycle life, and rate capability) and thermal stability compared to a conventional positive electrode (CC) Li [Ni0.8Co0.06Mn0.14]O2 without a concentration gradient. Electrochemical impedance spectroscopy showed that the high stability of the outer surface composition of Li[Ni0.64Co0.06Mn0.30]O2 is responsible for reduction in surface resistance and charge transfer resistance by decreasing the parasitic reaction with the electrolyte. These reduced resistances explain the superior rate capability of TSFCG positive electrodes.