Multifunctional amino-functionalized Zr-based metal-organic frameworks: A breakthrough in enhancing the stability and performance of Ni-rich cathode Li metal batteries in water-prone environments

Abstract

Striving to enhance the energy density of lithium metal batteries (LMBs) through the integration of Ni-rich cathodes is pivotal. However, these advanced batteries face significant challenges due to cathode degradation induced by water and the propensity for Li dendrite growth. To overcome these obstacles, we have synthesized amino-modified UIO-66 zirconium metal-organic frameworks (MOFs), U66N, which serve as a multifunctional separator layer to eliminate water and inhibit Li dendrite formation. Experimental evidence and theoretical computations collectively illustrate that U66N is highly effective in scavenging trace water from the electrolyte and facilitating the dissociation of Li salts, aided by the amino groups, thus preventing cathode degradation, improving electrochemical kinetics, and finely tuning the Li plating and stripping processes. In our testing, NCM811||Li cells equipped with the U66N separator preserve 77.1 % of their initial capacity after 200 cycles in an electrolyte contaminated with 300 ppm water, which is a markedly higher retention rate compared to cells with a conventional PP separator (24.7 %). Moreover, even in the electrolyte containing 600 ppm water, the NCM811||Li cells manage to retain 83.2 % of their capacity after 100 cycles. This study not only establishes a theoretical framework for the precise design of functionalized MOFs materials but also significantly advances the development of high-end battery systems with unparalleled energy density.