Prelithiated Li-Enriched Gradient Interphase toward Practical High-Energy NMC–Silicon Full Cell

Abstract

It is highly desirable to realize high-energy-density lithium-ion batteries consisting of nickel-rich layered oxide cathodes (Ni-rich NMC) and Si-based anodes. A critical challenge for Ni-rich NMC is its fast capacity degradation. In addition, the low initial Coulombic efficiency of the Si-based anode consumes the electrochemically active lithium from the cathode and decreases the energy density of full batteries considerably. We consider cathode and anode as a whole to simultaneously resolve the issues of both sides. Ni-rich LiNi0.65Mn0.20Co0.15O2 (LR-Ni65) consisting of a lithium-enriched gradient interphase layer (∼20 nm) is designed to supply excess electrochemically active lithium to compensate lithium loss at the anode and enhance cycling stability through regulating Li/Ni disorder in the cathode structure. We show that a LR-Ni65||Si/graphite pouch cell displays a capacity (3.29 Ah) greater than that for the counterpart using pristine Ni-rich NMC (2.95 Ah), as well as enhanced cycling stability with 88% capacity retention. The good compatibility with current Ni-rich NMC processing and facile synthesis make the as-fabricated cathode material promising for practical commercial application.