Ternary cathode material LiNi1/3Co1/3Mn1/3O2 (NCM) has attracted great attention, NCM electrode materials have been widely used and studied.However, NCM can only work in room temperature and can’t meet the needs of battery's rapid charging and discharging conditions, which limits its further application. To explore new materials and methods to improve the performance of lithium-ion batteries in extreme conditions becomes a hot topic.
Recently, Associate Professor WANG Lei’s group at Xinjiang Technical Institute of Physics & Chemistry (XTIPC) of Chinese Academy of Sciences constructed a lithium fast ion conductors modified NCM cathode material, which exhibited enhanced electrochemical performance at low temperatures and high rates. The study was published in Electrochimica Acta.
Researchers found that lithium fast ion conductors modified NCM samples increasing the discharge capacity of NCM from 86.4mA h/g to 127.7 mAh g-1 at -20°C and from 54.0 mAh g-1 to 141.7 mAh g-1 at the rate of 1 C after 100 cycles. And they showed a higher capacity compared with the maximum capacity (106mAh g-1) of modified ternary cathode material at -20°C on current report.
The high resolution transmission electron microscopy and scanning electron microscopy confirmed the existence of a thin coating layer (about 10 nm) on the original structure of NCM, which provided a stable surface protection to circumvent the disadvantages of NCM materials.
Researchers revealed that the increased lithium ion diffusion coefficients and the decreased charge transfer resistance are the primary factors that improve the discharge capacity at high rate and low temperature. The excellent discharge capacity of modified NCM can further promote its wide applications in electric vehicles.
This work was supported by the National Natural Science Foundation of China, the West Light Foundation of Chinese Academy of Sciences.
Figure：(a, b) Charge-discharge curve, (c, d) high rates performance, and (e) low temperature performance of pristine NCM and modified NCM(Image by XTIPC)
Associate Prof. WANG Lei
Xinjiang Technical Institute of Physics & Chemistry, CAS