The purpose of this study is to evaluate the deformation behavior of 3D printed specimens using the small punch tensile test method. Traditional tensile tests for assessing mechanical properties require a significant amount of material to produce uniaxial tensile specimens. In contrast, the small punch test method only requires 10 x 10 x 0.5 mm (width x length x thickness) thin plate specimens, providing a substantial economic advantage in specimen sampling and production. This method is particularly beneficial when it is impossible to produce specimens of the same size as uniaxial specimens, as it allows tensile testing with just the minimum sample required. In this study, we utilized fused deposition modeling 3D printing and considered various 3D printing parameters, such as layer height and volume fraction, while manufacturing the specimens. We then compared and analyzed the effects of these variables on tensile strength as measured by the small punch tensile test. Furthermore, we focused on investigating the applicability of this method to the deformation behavior of 3D printed specimens. We also examined the impact of laminating conditions, including layer height, printing speed, and laminating direction, on the failure modes observed after the small punch tensile test.

Improving the interfacial stability between cathode active material (CAM) and solid electrolyte (SE) is essential for enhancing the performance and durability of all-solid-state batteries (ASSBs). One promising method to achieve this is through surface coating with a chemically stable ion conductor, which helps suppress interfacial side reactions and improve long-term cycling stability. In this study, we deposited a uniform LiNbO3 (LNO) protective layer on NCA using particle atomic layer deposition (Particle ALD). This technique utilizes a self-limiting growth mechanism to ensure precise thickness control. We characterized the structural and chemical properties of the coated CAM with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), confirming the successful formation of a uniform LNO layer. Electrochemical evaluations revealed that LNO@NCA exhibited significantly improved capacity retention, maintaining 68.1% after 50 cycles at a 1C rate, compared to just 56.5% for the uncoated sample. This enhancement is attributed to the LNO layer's effectiveness in mitigating electrochemical side reactions. These findings demonstrate that Particle ALD-derived LNO coatings are an effective strategy for stabilizing CAM|SE interfaces and extending the cycle life of high-energy ASSBs.