Research on the electrochemical properties of vanadium boride coated on the surface of NCM811

• Published in: Journal of alloys and compounds 2022-12, Vol.927, p.166967, Article 166967
• Main Authors: Zhuang, Yan, Zhao, Yuhui, Bao, Yingqing, Zhang, Wei, Guan, Mingyun
• Format: Article
• Language: English
• Subjects: Electrical resistivity; Electrochemical analysis; Electrochemical performance; Electrodes; Electrolytes; Li-ion batteries; Ni-rich cathode; Phase transitions; Surface microstructure; Vanadium boride (V-B) coating; Vanadium compounds
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.166967

LiNi0.8Co0.1Mn0.1O2 (NCM811) has attracted much attention because of its high specific capacity. However, its poor electrical conductivity and the side reactions at the electrode/electrolyte interface result in unsatisfactory rate and cycling performance. A wet coating method is adapted to deposit a layer of vanadium boride (V-B) compounds on the surface of NCM811 to improve its performance. The capacity retention of NCM@ 1 V-B is increased about 15% after 500 cycles at 1 C, compared to the capacity retention of NCM. SEM and TEM images show that the thickness of the NCM@ 1 V-B coating layer is about 2.5 nm, which effectively inhibits the cracking of the surface microstructure at the cathode surface and reduces side reactions at the electrode/electrolyte interface. Thinner SEI film with less F-containing species forms on the electrode surface, less volume changes occurring the phase transition are responsible for the improved cyclability and rate capability for V-B coated NCM. •The electrochemical performance of NCM811 was improved by coated with vanadium boride (V-B) compounds.•V-B layer can inhibit cracking of material surface and reduce side reactions at electrode/electrolyte interface.•V-B coating layer can stabilize the SEI film on the surface and suppress the increase of the charge transfer resistance.