▎ 摘　　要

NOVELTY - Water-soluble elastic polysaccharide polymer i.e. substituted 6-(2-carboxy-4,5-dihydroxy-tetrahydropyran-3-yl)methoxymethyl-3-(6-carboxy-3,4-dihydroxy-tetrahydropyran-2-yl)methoxymethyl-4,5-dihydroxy-tetrahydropyran-2-carboxylic acid compound (I) is new. USE - The water-soluble elastic polysaccharide polymer is useful in water-soluble lithium-ion battery binder, lithium-ion battery electrode sheet, electrode active material and lithium-ion battery (claimed). ADVANTAGE - The water-soluble elastic polysaccharide polymer: has excellent chain flexibility and stronger water solubility; forms strong adhesive force, effectively prevents the electrode sheet from cracking and active material peeling, prolonging the service life of the battery. DETAILED DESCRIPTION - Water-soluble elastic polysaccharide polymer i.e. substituted 6-(2-carboxy-4,5-dihydroxy-tetrahydropyran-3-yl)methoxymethyl-3-(6-carboxy-3,4-dihydroxy-tetrahydropyran-2-yl)methoxymethyl-4,5-dihydroxy-tetrahydropyran-2-carboxylic acid compound of formula (I) is new. INDEPENDENT CLAIMS are also included for: preparing water-soluble elastic polysaccharide polymer comprising dissolving pullulan, initiator and sodium bromide in deionized water to obtain mixed solution A, adjusting pH of the oxidant solution into alkaline to obtain mixed solution B, adding the mixed solution B into the mixed solution A, reacting, adding quenching agent to the reaction solution and acidifying, adding precipitating agent to reaction solution for precipitation, and centrifuging to obtain crude product and purifying the crude product to obtain final product; water-soluble lithium-ion battery binder comprising binding agent including (I) and conductive materials; where the conductive material includes carbonaceous material, preferably carbon nanotubes, graphene, carbon aerogel, and/or MXene; preparing water-soluble lithium ion battery binder comprising adding (I) into deionized water, stirring, adding conductive materials to continue stirring, compounding, freeze-drying and grinding to obtain final product, where the mass ratio of conductive material to (I) is 0.2-4:1, preferably 0.4-2:1; lithium-ion battery electrode sheet comprising dissolving water-soluble lithium-ion battery binder in deionized water, stirring at 600-1200 revolutions/minute for 0.5-3 hours to dissolve to obtain binder solution, adding electrode active material into the binder solution, stirring in vacuum mixer at rate of 600-1200 revolutions/minute for 0.5-3 hours, mixing uniformly to obtain viscous slurry, coating the slurry evenly on the current collector and finally drying in vacuum oven at 100-130 ℃ for 8-15 hours to obtain final product; The electrode active material includes graphite and/or silicon-carbon composite material; the current collector includes copper foil, carbon-coated copper foil, aluminum foil, and/or carbon-coated aluminum foil, where preferably, used amount of water-soluble lithium ion battery binder is 3-30 wt.% of the addition of the electrode active material, preferably 5-20 wt.%; the loaded amount of the slurry on the current collector is 0.5-30 mg/cm, preferably 1-20 mg/cm.22 lithium ion battery comprising lithium-ion battery electrode sheet, positive and negative battery shells, shrapnel, gasket, lithium sheet, separator and electrolyte, where preferably, the separator includes glass fiber membrane and/or polyolefin porous membrane; and/or the electrolyte is a non-aqueous organic solvent and lithium salt.