Introduction of Novel Polymer Coating on the Surface of LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2 </sub>to Enhance Battery Cycling Performance under Harsh Conditions<sub> </sub>
발표자
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초록
내용
The Ni-rich cathode materials, LiNi0.8Co0.1Mn0.1O2 (NCM811) have advantages for high specific capacity and low cost. However, Ni-rich NCM is unstable at interface under harsh conditions such as high cut-off voltage and C-rate. Transition metal dissolution, HF attack, and cation disordering mutually influence each other and these parameters accelerate transition from layered structure to rock-salt of NCM, thus resulting in sharp capacity fade. To improve the issues on structural instability, surface coating is tried. FIB-TEM and EDS demonstrates the presence of uniform polymer layer. Cycling performance was tested in the voltage range of 2.8-4.3 V and 2.8-4.5 V at 2C for 200 cycles. After 200 cycle, surface-coated NCM shows better cycling stability, indicating higher capacity retention under both cut-off voltages. The ex-situ XPS, XRD matches well with cycling performance, implying that polymer coating layer contributes to maintain structural integrity of NCM and delay capacity decay.