Ultra-thin vapor chambers (UTVCs) are widely used to cool high-power electronics due to their excellent thermal conductivity. In this study, a UTVC of 82 mm × 58 mm × 0.39 mm with composite wick was prepared. The composite wick is composed of two layers of copper mesh and multiple spiral-woven meshes (SWMs), and the composite wick was applied in UTVC to improve liquid replenishment performance and temperature uniformity. Furthermore, the thermal performance of UTVCs with different support column diameters, filling ratios (FRs), and SWM structures was experimentally studied. The results found that the equivalent thermal conductivity (ETC) decreases as the diameter of the support column increases; the UTVC with 0.5 mm support column diameter has the highest ETC, at 3473 W/(m·K). Then, the effect of FR on the heat transfer performance of UTVCs with SWM numbers of 0, 1, 2, and 3 (0 SWMs, 1 SWM, 2 SWMs, 3 SWMs) is consistent, the 30% FR UTVC with 3 SWMs having the highest ETC, at 3837 W/(m·K). Finally, the increased number of SWMs can significantly improve the ultimate power of the UTVCs, the UTVC with 3 SWMs having the highest ultimate power, at 26 W. The above experimental studies indicate that the designed and manufactured UTVCs have great potential advantages in thermal dissipation for electronics.

The evolution of 5G technology necessitates effective thermal management strategies for compact, high-power devices. The potential of aluminum-based vapor chambers (VCs) as thermal management solutions is recognized, yet the heat transfer performance is limited by the capillary constraints of the wick structures. This study proposes a laser-sintered composite wick to address this limitation. Experimental evaluations were conducted on microgroove wicks (MW) and groove–spiral woven mesh composite wicks (GSCW), utilizing ethanol and acetone as the working fluids. The MW, characterized by a laser spacing of 0.2 mm and two passes, demonstrated a capillary rise of 52.90 mm, while the spiral woven mesh (SWM) achieved a rise of 61.48 mm. Notably, the GSCW surpassed both configurations, reaching a capillary height of 84.57 mm and a capillary parameter ($K/R_{eff}$) of 2.769 μm, which corresponds to increases of 90.15% and 43.76% over the MW and SWM, respectively. This study demonstrates an effective approach to enhancing the capillary performance of aluminum wicks, which provides valuable insights for the design of composite wicks, particularly for applications in ultra-thin aluminum VC.