couple high-capacity sulfur positive electrodes with earth-abundant sodium negative electrodes are unsurprisingly considered as a promising candidate. [8][9][10][11] In the process of cycle, the elemental sulfur of the cathode is dissolvated, reduced to form various soluble polysulfides, that is, S x 2− ions and radicals (1 ≤ x ≤ 8), and eventually the insoluble Na 2 S 2 and Na 2 S. [8,10,12] However, the practical applications are seriously hindered by several obstacles, in which the fundamental challenges are originated from the insulating properties of elemental sulfur and sodium sulfides, the volume changes at the cathode on cycling and the dissolution of sodium poly sulfides in the electrolyte. [9,[13][14][15] To date, extensive efforts have been made toward the enhancement of RT-Na/S batteries, including Na 2 S cathodes, [16,17] carbonaceous buffer matrixes, [12,18,19] a class of sodium polysulfides, [20,21] and the functional carbon-coated Nafion separator. [22] These approaches, while are validated to improve the cyclability of the RT Na-S batteries, tend to result in complicated synthetic processes and decreased theoretical capacity. In addition, it was suggested that the polar-polar interaction is a strong chemical interaction between polar sodium polysulfides and polar host materials. [23,24] Although there is no universal conclusion on the exact configuration of the interactions due to the complexity of carbon matrix, their similar effect in suppressing the polysulfide shuttle has also been reported in Li-S battery systems. [25][26][27] Instead of relying on polar-polar interactions, the suitably tailored hosts can bind sodium polysulfides through metal-sulfur bonding. Examples of such materials are sub-stoichiometric metal chalcogenides, MXene phases and metal-organic frameworks (MOFs). [28][29][30][31] In practice, these oxide and sulfide materials are able to bridge sodium polysulfides through both polar-polar Na-S(O) interaction and Lewis acid-base bonding, depending on the exposed facets to some extent. [25,32] However, to simply increase metal and/or binder content only neutralizes the advantageous energy density of the overall cell. Moreover, most of the sulfur-carbon electrode materials are directly prepared using elemental S and various carbon matrixes as started materials through vapor-infiltration or meltinfusion method. [8,10] As a result, the aggregated particles are Room temperature sodium-sulfur batteries have emerged as promising candidate for application in energy storage. However, the electrodes are usually obtained through infusing elemental sulfur into various carbon sources, and the precipitation of insoluble and irreversible sulfide species on the surface of carbon and sodium readily leads to continuous capacity degradation. Here, a novel strategy is demonstrated to prepare a covalent sulfur-carbon complex (SC-BDSA) with high covalent-sulfur concentration (40.1%) that relies on SO 3 H (Benzenedisulfonic acid, BDSA) and SO 4 2− as the sulfur source rather than elemental sulfur. M...