Fast Li+ Transport via Silica Network‐Driven Nanochannels in Ionomer‐in‐Framework for Lithium Metal Batteries

Abstract For the development of all‐solid‐state lithium metal batteries (LMBs), a high‐porous silica aerogel (SA)‐reinforced single‐Li + conducting nanocomposite polymer electrolyte (NPE) is prepared via two‐step selective functionalization. The mesoporous SA is introduced as a mechanical framework for NPE as well as a channel for fast lithium cation migration. Two types of monomers containing weak‐binding imide anions and Li + cations are synthesized and used to prepare NPEs, where these monomers are grafted in SA to produce SA‐based NPEs (SANPEs) as ionomer ‐in‐framework . This hybrid SANPE exhibits high ionic conductivities (≈10 −3 S cm −1 ), high modulus (≈10 5 Pa), high lithium transference number (0.84), and wide electrochemical window (>4.8 V). The resultant SANPE in the lithium symmetric cell possesses long‐term cyclic stability without short‐circuiting over 800 h under 0.2 mA cm −2 . Furthermore, the LiFePO 4 |SANPE|Li solid‐state batteries present a high discharge capacity of 167 mAh g −1 at 0.1 C, good rate capability up to 1 C, wide operating temperatures (from −10 to 40 °C), and a stable cycling performance with 97% capacity retention and 100% coulombic efficiency after 75 cycles at 1 C and 25 °C. The SANPE demonstrates a new design principle for solid‐state electrolytes, allowing for a perfect complex between inorganic silica and organic polymer, for high‐energy‐density LMBs.