Electrochemical stability of core–shell structure electrode for high voltage cycling as positive electrode for lithium ion batteries

The core–shell type cathode material Li[(Ni0.8Co0.1Mn0.1)0.8(Ni0.5Mn0.5)0.2]O2 (CS) for Li-ion battery was synthesized via co-precipitation method. The electrochemical and thermal properties of the core–shell structured Li[(Ni0.8Co0.1Mn0.1)0.8(Ni0.5Mn0.5)0.2]O2 were compared with those of the average composition of core–shell Li[Ni0.74Co0.08Mn0.18]O2 (ACCS) and the mixture of the core Li[Ni0.8Co0.1Mn0.1]O2 and the shell Li[Ni0.5Mn0.5]O2 material (MCS). The CS shows the enhanced electrochemical properties in a high voltage range (4.5 V and 4.6 V) as well as the typical cut-off voltage range (4.3 V). The capacity retentions of CS, core, and ACCS material were 94.2% (176.9 mAh g−1), 86.6% (172 mAh g−1), and 88.4% (169.3 mAh g−1) after 120 cycles, respectively.