Revealing the origin of enhanced structural stability for nickel-rich LiNi0.83Co0.11Mn0.06O2 cathodes in situ modified with multifunctional polysiloxane

Schematic illustration of the protective effect of the MPS layer on NCM83, the electrochemical performance comparison profiles of NCM83 and NCM83-2 electrodes and corresponding morphology and microstructure of cycled electrodes. [Display omitted] •MPS layer is synthesized via in situ hydrolysis-polycondensation of TEOS.•MPS layer not only serves as a physical isolation layer but also an ionic conductor.•MPS layer successfully inhibits H2 to H3 phase transition and reduces gas release.•The cell assembled with modified NCM83 delivers improved electrochemical performance. Multifunctional polysiloxane (MPS) layer is elaborately constructed on the surface of LiNi0.83Co0.11Mn0.06O2 (NCM83) particles via in situ hydrolysis-polycondensation of tetraethyl orthosilicate. Impressively, optimal NCM83 (NCM83-2) electrode covered with average 7 nm-thickness of fresh MPS layer delivers improved capacity retention ratio of 81.8 % after 150 cycles at 25 °C and retains the value of 78.7 % after 200 cycles at 60 °C and 1.0 C. Moreover, NCM83-2 electrode presents lower polarization degree with sluggish growth of the capacity platform. The significant advantages of NCM83-2 can be interpreted by the fact that the MPS layer effectively mitigates microcracks generation by inhibiting phase transition and lattice oxygen loss. Moreover, the MPS protective layer suppresses the thickening of cathode electrolyte interphase film and boosts the structural stability of NCM83 electrode to optimize electrochemical properties. Therefore, this strategy may provide promising enlightenments for preserving structural integrity and improving interfacial stability of nickel-rich cathodes for lithium-ion batteries.