Abstract
Solid electrolytes (SEs) offer promising avenues for improving both the energy density and safety of lithium-ion batteries (LIBs). However, the grain boundary resistance remains a significant hurdle that impact the performance of LIBs, particularly when utilizing SEs in powder form. In this study, we introduce a novel approach to reduce grain boundary resistance in Li1.3Al0.3Ti1.7(PO4)3 (LATP) via secondary crystallization induced by liquid electrolytes (LEs). By immersing nano-sized LATP powders in LiPF6/carbonates LEs, rapid aggregation and recrystallization into bulk micrometer-sized particles occur within minutes under ambient conditions. This secondary crystallization process alters the Li distribution within LATP bulk phase, substantially reducing the grain boundary resistance and enhancing Li-ion diffusivity. Consequently, the assembled LATP-modified commercial LiNi0.89Co0.07Mn0.04O2 cathode using LiPF6 electrolyte delivers a remarkable discharge capacity of 105.4 mAh g−1 at 4C, significantly superior to the bare electrode (44.7 mAh g−1). The recrystallized LATP enhances the transport properties and pathways of Li+ ions within the cathode material, especially at high current densities. Multinuclear and multi-dimensional solid-state NMR analysis reveal that active F− ions released from the hydrolysis of LiPF6 electrolytes act as mineralizing agent, facilitating rapid agglomeration and secondary growth of LATP grains. Our findings underscore the efficacy of secondary crystallization using LEs as a promising strategy for eliminating grain boundary resistance and facilitating fast Li-ion conduction of SEs, thereby advancing LIB performance.
Published Version
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