Ji-Woong Shin, Yun-Chae Nam, and Jong-Tae Son*
Department of Nano Polymer Science & Engineering, Korea National University of Transportation,
Chungju, Chungbuk 27469, Korea
The first commercialized cathode material, LiCoO2, suffers from disadvantages such
as high cost and toxicity and also possesses safety problems. The nickel-rich LiNi0.9Mn0.1O2
cathode material, used as an alternative to LiCoO2, has highly reversible capacity and high
energy density. So, the nickel-rich LiNi0.9Mn0.1O2 cathode material is widely used as an alternative
to LiCoO2 due to its highly reversible capacity and high energy density. However,
LiNi0.9Mn0.1O2 has several disadvantages as well, such as poor cycle performance and poor
thermal instability. To address these problems, we synthesized a new material, LiNi0.5Mn0.5O2,
as a shell on the surface of a core to suppress the surface degradation. The new material showed
high structural and thermal stabilities and could also maintain a high capacity. The capacity
retention of the core-shell cathode (87.7%) was better than that of the core cathode (76.9%) after
50 cycles. Analysis using differential scanning calorimetry revealed that the heat generation in
the core-shell cathode (65.9 Jg-1) was lower than that in the core cathode (559.7 Jg-1).
Keyword : Cobalt-Free, Core-Shell Structure, Cathode Material