| 摘要 |
PURPOSE: A secondary battery is provided to have excellent high voltage performance, thereby being used for a medium-to-large device which requires high temperature stability, long cycle performance, and high rate performance. CONSTITUTION: A secondary battery comprises: a positive electrode active material which is a lithium transition metal oxide indicated in chemical formula 1: Li(Ni_xMn_yCo_z)O_2, and a negative electrode active material which is a natural graphite. The BET of the natural graphite is 2.5-2.6 m^2/g, the loading amount of a positive electrode is 2.3-2.4 mAh/cm^2 and the loading amount of a negative electrode is 2.5-2.7 mAH/cm^2. In chemical formula 1, 0.2ΔxΔ0.3, 0.6ΔyΔ0.7, 0<zΔ0.2, x+y+z=1. The natural graphite is surface-treated and the surface treatment is one or more selected from chemical surface treatment and heat treatment. |
