A novel electrolyte approach for a lithium-sulfur secondary battery is presented, realistically portrayed on pouch cell level, with its decisive element being a new electrolyte system, a mixture of a hydrofluoro ether and sulfolane. The hereby suppressed polysulfide solubility enables high discharge capacities and requires only very low electrolyte excess (< 2.6 μLmgS^-1) achieving high coulomb efficiencies above 94% (capacity retention of 77% over 40 cycles) without the necessity of adding lithium nitrate for shuttle suppression. Due to the low volatility, this adopted electrolyte concept promises significant benefits for large operational battery units.