Towards high-performance lithium metal batteries: sol electrolyte generated with mesoporous silica

Abstract

High-energy lithium metal batteries are considered as a promising alternative for next-generation energy storage systems. However, the uncontrolled lithium-dendrite growth due to the inhomogeneous lithium electrochemical deposition prevents lithium batteries from commercial application. Herein, a sol electrolyte was prepared by the addition of mesoporous silica, SBA-15 to the liquid ester-based LiPF6 electrolyte to induce the formation of a dense protective layer on the lithium metal surface and inhibit the uncontrolled growth of lithium dendrites and the electrolyte consumption. Mesoporous silica with ordered hexagonal nanochannels and abundant surface silicon hydroxyl groups not only facilitates the formation of the sol electrolyte, but also adsorbs the electrolyte, leading to homogeneous lithium ion distribution. The sol electrolytes would generate a dense protective layer on the lithium metal and a robust CEI film on the surface of the cathode materials through an in situ gelation process, suppressing the uncontrolled lithium dendrite growth and improving the stability of the electrolyte. Consequently, high electrochemical performance was demonstrated with the Li||LiNi0.5Co0.2Mn0.3O2 (NCM523) full cells with the sol electrolyte. This work provides a new strategy for improving the performance of lithium metal batteries through the formation of sol electrolytes.