An artificially tailored functional layer on Li-rich layer cathodes enables a stable high-temperature interphase for Li-ion batteries

The unstable electrode-electrolyte interphase, poor rate capability, and severe lattice oxygen release of Li-rich layer oxides (LRNCM) severely limit their commercial application. Herein, an ultrathin Li2SiO3 protective layer with super toughness and functionality is uniformly constructed on the surface of LRNCM by atom layer deposition (ALD), which can not only suppress the side reactions of the electrode-electrolyte but also effectively alleviate the fragmentation of secondary particles (caused by the lattice stress), eventually leading to a huge improvement in structural and electrochemical stability, especially under harsh test conditions (high voltage or high temperature). Benefiting from these functionalized effects, the LRNCM electrode coated with 10 ALD cycles exhibits higher electrochemical stability at 60 degrees C, where its capacity retention rate still remains at 86.1% at 1 C after 100 cycles (vs. only 26% for bare LRNCM), and its rate capacity can also reach 188.7 mA h g(-1) at 5 C. Hence, this work provides a significant pathway in overcoming capacity decay and electrode/electrolyte interface deterioration of LRNCM cathodes under extreme environments to broaden their application scenarios.

Automated summary

An ultrathin Li2SiO3 protective layer was uniformly deposited on the surface of LRNCM by ALD, addressing the instability issues of LRNCM. The coated LRNCM electrode exhibited improved structural and electrochemical stability, with high capacity retention and rate capability, even under extreme conditions.