Conformal poly(ethyl α-cyanoacrylate) nano-coating for improving the interface stability of LiNi_0.5Mn_1.5O₄

Highlights: • A strategy to modify the interface stability of LiNi_0.5Mn_1.5O₄ is proposed. • The conformal nano-coating of poly(ethyl α-cyanoacrylate) is multifunctional. • Polymer coating suppresses undesired interfacial reaction of LiNi_0.5Mn_1.5O₄. • Enhanced electrochemical performance is obtained in modified LiNi_0.5Mn_1.5O₄. - Abstract: Undesired interfacial reaction between the high voltage spinel LiNi_0.5Mn_1.5O₄ and commercial organic electrolyte is one of the most essential obstacles for the application of cathode material LiNi_0.5Mn_1.5O₄ in lithium-ion batteries (LIBs). Here, to amend the high voltage cathode/electrolyte interface of LiNi_0.5Mn_1.5O₄, we proposed a conformal nano-coating strategy by in-situ polymerization of poly(ethyl α-cyanoacrylate) (PECA) on its surface. The electrochemical measurement results demonstrated that the conformal PECA nano-coating film, acting as high voltage polymer electrolyte, transition metallic ions blocking layer, and buffer layer against electrolyte erosion and particle cracks, can successfully decrease polarization and enhance capacity retention during cycling of LiNi_0.5Mn_1.5O₄. This work will inspire extensive and intensive research on the interface modification of LIBs.