Achieving superior critical current density and rate performance in solid-state lithium batteries via vertically aligned LATP arrays

Abstract

A key challenge in solid-state lithium batteries is enhancing critical current density (CCD) and rate performance by promoting efficient ion transport within the electrolyte. This study presents a novel solid-state electrolyte utilizing vertically aligned lithium aluminum titanium phosphate (LATP) arrays, synthesized via a freeze-casting technique. By optimizing the contrast in ionic conductivity between the LATP scaffold and the embedded polymer, we established an effective ion transport pathway. The vertically aligned structure significantly improved ionic conductivity, achieving a CCD of 10 mA cm⁻² and reducing interfacial contact resistance. The Li|PEGDA/o-LATP||Li cells demonstrated excellent cycling stability, maintaining consistent performance over 4500 h, with minimal polarization changes after 1600 h at 2.0 mA cm⁻². The Li||PEGDA/o-LATP||LFP full cells maintained a specific capacity of 164.4 mAh g⁻¹ at 0.1 C and 97.1 mAh g⁻¹ at 5.0 C, retaining 71.1 % of their capacity after 2000 cycles at 1.0 C. The Li||PEGDA/o-LATP||NCM811 full cells delivered discharge capacities of 201.3 mAh g⁻¹ at 0.2 C and 162.4 mAh g⁻¹ at 2.0 C under a high voltage of 4.5 V, with 92.4 % capacity retention after 200 cycles. This work highlights the importance of innovative electrolyte design in achieving high CCD values, laying the groundwork for next-generation solid-state batteries with improved performance.