TECHNOLOGY FOCUS - POLYMERS - Preparation: No general preparation given. Preferred Polymer: The cationic-group-containing repeating unit is of formula (I or Ia) or (II). The anionic-group-containing repeating unit is of formula (III). The polymer further contains a saturated-group-containing repeating unit of formula (IV).X-containing ring=2-30C 3-13-membered ring containing hetero atom;X=-N(R')(R"), -S(R') or -P(R')(R");R1-R4=H or 1-30C alkyl, 1-30C alkoxy, 6-30C aryl, 7-30C arylalkyl, 6-30C aryloxy, 3-30C heteroaryl, 3-30C heteroaryloxy, 4-30C cycloalkyl or 3-30C heterocycloalkyl (all optionally substituted);X'=-N(R')(R")(R"'), -S(R')(R"), -OP(R')(R")(R"') or P(R')(R")(R"');A=bond or 1-30C alkyl, 6-30C aryl, 7-30C arylalkyl, 1-30C heteroaryl, 4-30C cycloalkyl or 1-30C heterocycloalkyl (all optionally having -CO-, -O-, -COO- or -OCO-, -NH-CO- or -CO-NH-, -NH-SO2- or -SO2-NH-, -S-, -S(O)-, -SO2-, -SO2-O- or -O-SO2-, -NH-, -(CH2)n-, -(CH2O)n-, -(CH2CH2O)n-, or -(CH(CH3)CH2O)n-);n=1-20;R',R",R'"=1-30C alkyl, 1-30C alkoxy, 6-30C aryl, 6-30C aryloxy, 3-30C heteroaryl, 3-30C heteroaryloxy, 4-30C cycloalkyl, or 3-30C hetero cycloalkyl;Z'=-C(=O)O, -OS(=O)2O, -OS(=O)O, -S(=O)O, -OP(=O)(O)2, or -P(=O)(O)2;n'=1 or 2;W'=carboxy, hydroxy, amine, amide, imide, nitrile, sulfone, halo, silane or Si(B')(B")(B"');B',B",B"'=1-20C alkyl, 1-20C alkoxy or halo;andR8-R10=R1.The polymer has molar fraction of cationic group greater than molar fraction of anionic group, molar fraction of anionic group greater than molar fraction of cationic group or equal molar fractions of anionic and cationic groups. If the cationic group molar faction is x, the anionic group molar faction is y, the anionic fraction with a counter ion is y-m, and the neutral fraction is z, and when n of Z' power (n-) is 1, then m,x is 0.05-0.5, y is 0.5-0.95 and x+y is 1, when n of Z' (power n-) is 2, then x is less than 2y, m is 0.5x, x is 0.05-0.5, y is 0.25-0.475 and x+y is 0.525-0.75, or when n of Z' (power n-) is 1, then m,x is 0.05-0.50, y is 0.25-0.94, z is 0.01-0.5, and x+y+z is 1, when n of Z' (power n-) is 2, then x is less than 2y, m is 0.5x, x is 0.05-0.50, y is 0.125-0.47 and z is 0.01-0.5, when the anionic group has the larger molar fraction. If the cationic fraction with a counter ion is x-m, and when n of Z' (power n-) is 1, then 0.5-0.95, m,y is 0.05-0.5 and x+y is 1, when n of Z' (power n-) is 2, then m is 2y, x is 0.5-0.95, y is 0.025-0.25, and x+y is 0.75-0.975, or when n of Z' (power n-) is 1, then x is 0.25-0.94, y,m is 0.05-0.50, z is 0.01-0.5, and x+y+z are 1, and when n of Z' (power n-) is 2, then m is 2y, x is 0.25-0.94, y is 0.025-0.25 and z is 0.01-0.5, when the cationic group has the larger molar fraction. If the polymer has equal molar fractions of the anionic and cationic groups, and when n of Z' (power n-) is 1, then x,y is 0.5, when n of Z'(power n-) is 2, x is 0.5 and y is 0.25, or when n of Z'(power n-) is 1, then x,y is 0.25, z is 0.01-0.5 and x+y+z are 1, when n of Z'(power n-) is 2, x is 0.25-0.495, y is 0.125-0.2475 and z is 0.01-0.5. The polymer is of formula (ia), (ib), (ic), (id) or (iD), or (ie).m,y+2z,x'y",a=0.05-0.5;x,b=0.5-0.95;x+m,x+y+2z,a+b,x'+y'+z',x"+y"+z'=1;x",y'=0.25-0.94;z'=0.01-0.5;andn=1. EXAMPLE - 50 mol% acryloyloxy ethyl trimethylammonium chloride, 40 mol% sodium acrylate, and 10 mol% 2-hydroxyethyl acrylate were loaded into a reaction container equipment with an agitator and a condenser, the total weight of the monomers was 20 g. 0.023 g 2,2'-Azobis(2-methylpropionamidine) dihydrochloride as a reaction initiator and 70 g pure water were added into the vessel containing the monomers. Nitrogen bubbling was performed for 30 minutes to remove dissolved oxygen in solution, and then, the temperature of the reaction vessel was increased to a temperature of 60 degrees C to perform polymerization. After 30 minutes of polymerization, 30 g deoxygenated water was added, and the reaction was performed for 4 hours. Then, the temperature of the reaction vessel was lowered to room temperature to stop the polymerization reaction. A reaction product was slowly added to 10 L methanol to prepare a precipitate. The precipitate was filtered, and dissolved in water to prepare 10 wt% solution, and precipitated in 10L methanol, a pure polymer (poly(acryloyloxyethyl trimethylammonium chloride-co-acrylate-co-2-hydroxyethyl acrylate)) was obtained. The lithium secondary battery manufactured using the obtained polymer showed capacitance retention ratio of 95%.