Solid-state sodium-ion batteries with sodium metal anodes possess high safety and reliability, which are considered as a promising candidate for the next generation of energy storage technology. However, poor electronic and ionic conductivities at the interface between electrodes and solid-state electrolytes restrict its practical application. Herein, we demonstrate a β″-Al₂O₃ electrolyte with a vertically porous-dense bilayer structure to solve this problem. The carbon-coated vertically porous layer serves as a high mass-loading host for Na₃V₂(PO₄)₃ cathode and provides fast electronically and ionically conductive pathways. In addition, the dense layer is produced to prevent sodium dendrite growth and improve mechanical strength of β″-Al₂O₃ electrolyte. Experimental results show that the cathode loading in vertically porous layer can reach to 8 mg cm⁻², and the porous-dense bilayer β″-Al₂O₃ electrolyte-based battery exhibits a reversible specific capacity of 87 mAh g⁻¹ and a capacity retention of 95.5% over 100 cycles at a current density of 0.1 C, which is superior to that of the traditional dense β″-Al₂O₃ electrolyte-based battery. This work based on electrolyte structure design represents an efficient strategy for the development of solid-state sodium-ion batteries with high mass-loading cathode.

具有金属钠负极的固态钠离子电池具有较高的安全性和可靠性，被认为是下一代储能技术的有希望的候选者。然而，电极和固态电解质之间界面处的电子和离子导电性较差，限制了其实际应用。在此，我们展示了一种具有垂直多孔致密双层结构的 β″-Al ₂ O ₃电解质来解决这个问题。碳涂层垂直多孔层作为 Na ₃ V ₂ (PO ₄ ) ₃的高质量负载主体阴极并提供快速的电子和离子导电通路。此外，产生致密层以防止钠枝晶生长并提高β″-Al ₂ O ₃电解质的机械强度。实验结果表明，垂直多孔层的正极负载量可达8 mg cm ^-2，多孔致密双层β″-Al ₂ O ₃电解质基电池的可逆比容量为87 mAh g ^-1和a在0.1 C的电流密度下，100次循环的容量保持率为95.5%，优于传统的致密β″-Al ₂ O ₃基于电解质的电池。这项基于电解质结构设计的工作代表了开发具有高负载量阴极的固态钠离子电池的有效策略。