Tin-Doped LATP Electrolytes Incorporated with Nickel-Rich Ternary Cathodes for Solid-State Pouch Cells Exhibiting High-Rate Capability and Excellent Cycling Stability

High Resolution Image Download MS PowerPoint Slide This study explores the use of Sn-doped sodium superionic conductor (NASICON)-type Li 1+ x Al x Ti 2– x (PO 4 ) 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 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) and LiNi 0.6 Co 0.2 Mn 0.2 O 2 (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 Sn 4+ and Ti 4+ in NASICON-type lattices reduce distortion, but Sn 4+ ’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 cm 2 s –1 and 1.47 × 10 –8 cm 2 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.