Tin-Doped LATP Electrolytes Incorporated with Nickel-Rich Ternary Cathodes for Solid-State Pouch Cells Exhibiting...

This study explores the use of Sn-doped sodium superionic conductor (NASICON)-type Li_1+x Al _x Ti_2-x (PO₄)₃ (LATP) electrolytes in solid-state pouch cells with Ni-rich ternary cathodes that exhibit high-rate capability, low inner resistance, and superior cyclability. The pouch cell configuration includes two types of Ni-rich NCM cathodes, LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) and LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622), paired with artificial graphite anodes (MG11) and synthesized LATP-containing composite solid electrolytes (CSEs). These cells demonstrate superior cyclic performance with high energy and power densities. Sol-gel and thermal calcination produced highly ionic conductivity Sn-LATP powders for CSEs. The equivalent ionic radii of Sn⁴⁺ and Ti⁴⁺ in NASICON-type lattices reduce distortion, but Sn⁴⁺'s greater Pauling electronegativity (∼1.96) improves the stability. The Sn-LATP powders in CSEs enhance the high-rate capabilities and cyclic stability of the solid-state pouch cells. NCM523 and NCM622 pouch cells with cathode-equipped pouches showed enhanced rate capability, with NCM523 achieving 58.9% capacity retention at 3C to 0.2C and NCM622 achieving 91.1% retention and ∼99.5% Coulombic efficiency over 200 cycles. Sn-LATP powders dramatically lower ESR values, according to the equivalent circuit impedance analysis. The diffusion coefficients for NCM523||Sn-LATP||MG11 and NCM622||Sn-LATP||MG11 pouch cells are 2.18 × 10^-8 cm² s^-1 and 1.47 × 10^-8 cm² s^-1, respectively, while the energy densities of NCM523||Sn-LATP||MG11 and NCM622||Sn-LATP||MG11 pouch cells are 132 and 172 Wh kg^-1 at high-power densities of 717 and 778 W kg^-1, respectively. The optimum CSE layer design using Sn-LATP particles presented in this work may lead to enhanced solid-state energy storage devices.