Abstract:
A lithium secondary battery is produced by employing a charging method where a positive electrode upon charging has a maximum achieved potential of 4.3 V (vs. Li/Li+) or lower. The lithium secondary battery contains an active material including a solid solution of a lithium transition metal composite oxide having an α-NaFeO2-type crystal structure. The solid solution has a diffraction peak observed near 20 to 30° in X-ray diffractometry using CuKα radiation for a monoclinic Li[Li1/3Mn2/3]O2-type before charge-discharge. The lithium secondary battery is charged to reach at least a region with substantially flat fluctuation of potential appearing in a positive electrode potential region exceeding 4.3 V (vs. Li/Li+) and 4.8 V (vs. Li/Li+) or lower. A dischargeable electric quantity in a potential region of 4.3 V (vs. Li/Li+) or lower is 177 mAh/g or higher.
Abstract translation:通过采用充电方法制造锂二次电池,其中充电时的正极的最大实现电位为4.3V(相对于Li / Li +)以下。 锂二次电池含有具有α-NaFeO 2型晶体结构的锂过渡金属复合氧化物的固溶体的活性物质。 固体溶液在使用CuKalpha辐射的X射线衍射法中观察到的衍射峰接近20〜30°,在单次Li / LiNi / LiNiO3 / LiNi2O3型充电 - 放电之前。 锂二次电池被充电至少达到在超过4.3V(相对于Li / Li +)和4.8V(相对于Li / Li +)以下的正电极电位区域中出现的具有基本平坦的电位变动的区域。 4.3V(相对于Li / Li +)以下的电位区域的可放电电量为177mAh / g以上。