We demonstrate a disposable aqueous primary battery chemistry that comprises environmentally benign materials of the sulfur cathode and Zn anode in a 1 M ZnCl₂ aqueous electrolyte. The Zn–S battery shows a high energy density of 1083.3 Wh kg⁻¹ for sulphur with a flat discharge voltage plateau around 0.7 V. When operating at a high mass loading of 8.3 mg cm⁻² for sulfur in the cathode, the battery exhibits a very high areal capacity of 11.4 mA h cm⁻² and areal energy of 7.7 mW h cm⁻².