A‐LLTO Nanoparticles Embedded Composite Solid Polymer Electrolyte for Room Temperature Operational Li‐metal Batteries

Abstract Solid‐state batteries (SSBs) have the potential to revolutionize the current energy storage sector. A significant portion of the current development of electric vehicles and the electrification of various appliances relies on Lithium (Li)‐ion batteries. However, future energy demands will require the development of stronger and more reliable batteries. This report presents a novel solid state electrolyte (SSE) composed of a self‐healing composite solid polymer electrolyte (CSPE) matrix and aluminum‐doped (Li_0.33La_0.56)_1.005Ti_0.99Al_0.01O₃ (A‐LLTO) nanofillers. The CSPE contains Jeffamine ED‐2003 monomer, Benzene‐1,3,5‐tricarbaldehyde (BTC) crosslinker dissolved in a 1:1 ratio of Dimethylformamide (DMF) to LiPF₆, and a certain amount (x) of A‐LLTO nanofillers (x = 5, 7.5, 10, 12.5%). A CSPE containing x‐amount of A‐LLTO fillers (referred to as CAL‐x%) demonstrates excellent ion‐conducting properties and stable battery performance. The CAL‐10% demonstrates 1.1 × 10⁻³ S cm⁻¹ of ionic conductivity at room temperature (RT). A‐LLTO nanofillers dispersed uniformly within the polymer matrix form a percolation network, which is believed to improve ionic conductivity and the diffusion of Li⁺ ions. The CR‐2032 cell, consisting of LiFePO₄ (LFP)║CAL‐10%║Li, at RT offers an initial discharge capacity of ≈165 mAh g⁻¹ at 0.1C rate for 120 cycles with 98.85% coulombic efficiency (C.E.).