METHOD FOR CHARGING LITHIUM SULFUR BATTERY

摘要

Provided is a method for charging a lithium sulfur battery to improve cycle lifetime by controlling charge/discharge condition, and a lithium sulfur battery. The method comprises the condition such that the cut-off voltage of n-th charging cycle is different from the cut-off voltage of at least one cycle from (n-1)-th to first cycles, and the charged amount at the n-th charging cycle is 50 % or less of the capacity of a battery. Preferably the cut-off voltage of n-th charging cycle is 2.5-3.2 V; and the cut-off voltage of at least one cycle from (n-1)-th cycles to first cycles is 2.30-2.50 V. The lithium sulfur battery comprises a positive electrode comprising a positive electrode active material and a negative electrode comprising a negative electrode active material. Preferably the positive electrode active material is selected from the group consisting of elemental sulfur, Li2Sn (n>=1), an organic sulfur compound and a carbon-sulfur polymer (C2Sx, x = 2.5-50, and n>=2); and the negative electrode active material is a lithium metal or a lithium alloy.