Carbon replica constructed of three-dimensional, ordered mesopores was employed as the conductive framework for the composite electrode in Li-sulfur all-solid-state batteries. Using a gas-phase mixing method under various conditions, elemental sulfur was introduced into the mesopores with an average diameter of 12 nm. The all-solid-state cells consisted of the sulfur-carbon replica composite cathode, thio-LISICON solid electrolyte, and Li-Al alloy anode. The cells produced discharge capacities of approximately 1500 mAh g −1 in the 1 st cycle, which is comparable to the theoretical capacity of sulfur. Thermogravimetric and X-ray diffraction analyses revealed that sulfur deposited inside the mesopores is the main contributor to the excellent performance of the battery. However, sulfur strongly interacted with the carbon replica, reducing the thickness of the carbon wall from 7 to 4 nm. This structural change in the carbon matrix triggered the deterioration of battery performance, especially the cycling capability. Optimizing the sulfur deposition conditions could therefore enhance the performance of batteries using such composite electrodes. The all-solid-state Li-sulfur battery is a promising candidate for next-generation energy storage systems due to its large theoretical capacity (1672 mAh g −1 ), the abundance and low toxicity of sulfur, and the non-flammable nature of solid electrolytes. [1][2][3][4][5][6] In addition, the solid electrolyte prevents the dissolution of lithium polysulfides Li 2 S n (3 ≤ n < 8) into the electrolyte during charge-discharge reactions, which is a serious issue for liquid-type Li-sulfur batteries. 7,8 However, the low electrical conductivity of sulfur (5 × 10 −30 S cm −1 ) 9 lowers its utilization ratio, thus deteriorating the rates and cycle capabilities of these batteries. To overcome such problems, carbon materials have been employed as the framework for sulfur composite electrodes, because their superior electrical conductivities can enhance the charge-discharge characteristics of Li-sulfur batteries. 1,2,4,10 In particular, the large volume changes of sulfur itself during battery reaction also hamper reversible charge-discharge.11,12 Therefore, mesoporous carbon materials containing highly ordered mesopores within their matrix are widely used for this purpose, and are expected to be suitable candidates for the preparation of composite sulfur-carbon electrodes.2-4,13 These mesoporous carbon materials have unique characteristics such as large surface area (e.g. CMK-3: ∼2000 m 2 g -1 )10 and large amount of mesopores in the structure. The mesopores accommodate more sulfur and suppress the sulfur volume change in the composite. Although CMK-3 with ordered two-dimensional mesopores (∼2 nm) is an attractive carbon matrix candidate, its cylindrical pores do not facilitate contact between the sulfur within and the solid electrolyte, 2,3 while both ionic and electronic conduction pathways are necessary for the electrode to function. Therefore, a novel composite electrode design could i...