Electrochemical Properties of Nanosized Li₂MnO₃·Li(Ni_0.8Co_0.15Al_0.05)O₂ Composite Cathode Powders

摘要

Nanometer-sized LiNi0.8Co0.15Al0.05O2 and 0.6Li2MnO30.4LiNi0.8Co0.15Al0.05O2 powders are preparedby high-temperature flame spray pyrolysis. The 0.6Li2MnO30.4LiNi0.8Co0.15Al0.05O2 compositepowders post-treated at 700 and 800C exhibit mixed-layer crystal structures comprising layeredLi2MnO3 and layered LiNi0.8Co0.15Al0.05O2 phases. The mean sizes of the composite powders post- treated at 700 and 800C are 127 and 180 nm, respectively. The layeredayered composite powdershave sizes in the nanometer range with a slightly aggregated structure, whereas the layeredLiNi0.8Co0.15Al0.05O2 powders have sizes in micrometer range with a hardly aggregated structure. The-1 discharge capacity of the LiNi0.8Co0.15Al0.05O2 powders decreases from 163 to 95 mAh g after 50cycles with a capacity retention of 58%. The discharge capacity of the-1 0.6Li2MnO30.4LiNi0.8Co0.15Al0.05O2 composite powders decreases from 235 to 200 mAh g after 50cycles with a capacity retention of 85%.