Synthesis design of interfacial nanostructure for nickel-rich layered cathodes

Abstract

High-energy nickel-rich layered oxide cathodes are one kind of the promising materials to electric vehicles powered by lithium-ion batteries. However, grain boundary structure and chemistry disintegration show the most serious challenges for these cathodes at long-term cycles, particularly under extreme temperatures and high voltages. Herein, we present a sustainable synthesis route to achieve a uniform surface/interface-coating of nickel-rich layered oxide secondary particles as well as grain boundaries. The obtained cathodes demonstrate dramatically enhanced rate capability and cycling stability in a wide temperature range from −40 ℃ to 60 ℃ even charged to the high cut-off voltage of 4.5 V. Moreover, the cathodes display a high humidity tolerance with scarcely any sign of impurity after exposure to an atmosphere with 98% relative humidity. The highly dense and resistive fluorine- and cobalt-rich interphase structures can effectively protect the particles from the simultaneous degradation of surface structure and side reactions with electrolytes at cycling. This facile interfacial nanostructure is further demonstrated with lower interface energy, facilitating the lithium-ions transport with lower interface impedance and improved stability. Thereby, this synthesis perspectives provide the new insights of nickel-rich lithium cathodes at grain boundary dimensions.