Polysulfide dissolution control: the common ion effectElectronic supplementary information (ESI) available: Experimental details, SEM, EDX and viscosity data. See DOI: 10.1039/c2cc36986a

A Li-sulfur cell with a high discharge capacity of over 1300 mAh g −1 at a C/10 rate, and a controlled overcharge amount less than 1%, was manufactured by synthesizing a carbon-sulfur nano-composite via a wet milling process, and suppressing polysulfide dissolution using an electrolyte with a highly concentrated lithium salt. A Li-sulfur cell with a highly concentrated electrolyte can suppress overcharge amount less than 1% by common ion effect.