Tailoring Vertically Aligned Inorganic‐Polymer Nanocomposites with Abundant Lewis Acid Sites for Ultra‐Stable Solid‐State Lithium Metal Batteries

Abstract Nanocomposite solid polymer electrolytes are considered as a promising strategy for solid‐state lithium metal batteries (SSLMBs). However, the randomly dispersed fillers in the polymer matrix with limited Li⁺ transference number and insufficient ionic conductivity severely sacrifice the ion transport capacity, thus restricting their practical application. To tackle these issues, a magnetic field‐assisted alignment strategy is proposed to disperse the vertically aligned akaganéite nanotube in the polymer matrix as an inorganic‐polymer nanocomposite solid‐state electrolyte for ultra‐stable SSLMBs. The metal cations as Lewis acid sites can grab anions to promote the dissociation of Li salts while the sufficient oxygen and hydroxyl functional group offer abundant Li‐ion migration sites for favored ion transportation. At the same time, the vertically aligned akaganéite/polymer interface combined with the above synergistic effects can establish oriented channels inside solid‐state electrolyte, which significantly elevates its ionic conductivity. Specially, an organic‐inorganic dual‐layer solid‐electrolyte interface is formed to uniform Li deposition and suppress the dendrite growth. The beneficial effect of the vertically aligned network is also demonstrated in full cell and pouch cell where remarkable 2000 cycles with a capacity decay of 0.012% per cycle can be achieved.