Metal organic frameworks and energy storage system including this

An energy storage system comprising a slurry layer containing an electrode active material, the electrode active material comprising a metal-organic framework:

• wherein said metal-organic framework comprises the coordination bond between metals and organic ligands, the organic ligands having one or more species selected from the following group consisting of a first expression, a second expression, and a third expression;
• wherein in the first expression, the second expression, or the third expression, X is selected independently from the group consisting of OH, NH2, SH, SeH, and COOH, and Y is selected independently from the group consisting of H, CN, F, Br, OH, and OCH3.