Ni‐rich LiNi0.8Co0.1Mn0.1O2(NCM811) has been considered as a promising cathode material for high energy density lithium‐ion batteries. However, it experiences undesirable interfacial side‐reactions with the electrolyte, which lead to a rapid capacity decay. In this work, a homogeneous precipitation method is proposed for forming a uniform silicon dioxide (SiO2) coating on the NCM811 surface. The strong Si−O network provided a stable protective layer between the NCM811 active material and electrolyte to improve the electrochemical stability. As a result, the NCM811@SiO2cathode showed superior cycling stability (84.9 % after 100 cycles at 0.2 C) and rate capability (142.7 mA h g−1at 5 C) compared to the pristine NCM811 cathode (56.6 % after 100 cycles, 127.9 mA h g−1at 5 C). Moreover, the SiO2coating effectively suppressed voltage decay and pulverization of the NCM811 particles during long term cycling. This uniform coating technique offers a viable approach for stabilizing Ni‐rich cathode materials for high‐energy density lithium‐ion batteries.
Macroporous Nb2O5(MP‐Nb2O5) has been synthesized using dispersed polystyrene microspheres (PS) as template followed by annealing in air. The structural characterization showed that the diameters of the macropores are around 200 nm and the average particle size of the composition is 20–50 nm. XPS revealed the presence of low valence Nb4+and oxygen vacancies on the surface of the resulting product introduced during the pyrolysis of PS. Such a unique combination of macroporous nanostructure and tetravalent niobium ions enables the electrode with superior lithium ion insertion properties, such as high specific capacity (≈190 mA h g−1at 0.5C) and rate capability. Even at a current density of 1.6 A g−1, an average capacity of 129.2 mA h g−1can still be obtained. These findings demonstrate MP‐Nb2O5is a promising candidate for high‐rate lithium ion storage applications.
more » « less- NSF-PAR ID:
- 10236125
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemNanoMat
- Volume:
- 2
- Issue:
- 7
- ISSN:
- 2199-692X
- Page Range / eLocation ID:
- p. 675-680
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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