TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred materials: The polymer particles have 50-100% gel content (G1), calculated as the component insoluble in an electrolyte comprising a 1 M solution of LiPF6 in a mixed solvent of propylene carbonate-ethylene carbonate-diethyl carbonate-dimethyl carbonate-methylethyl carbonate (20degreesC vol. ratio = 20:20:20:20:20). The polymer contains essentially no structural units derived from monomers containing nitrile. (A) is at least one from acrylic acids having opt. substituted alkyl in the alcohol residue, methacrylic acids and crotonic acid. (B) is at least one from mono-ethylenically unsaturated monocarboxylic acids chosen from acrylic acids, methacrylic acids and crotonic acid, mono-ethylenically unsaturated dicarboxylic acids chosen from maleic acid, fumaric acid, citraconic acid, mesaconic acid, glutaconic acid and itaconic acid, and their acid anhydrides. (C) is at least one from 1,3-butadiene, 1,3- and 2,3-pentadiene, isoprene, 1,3- and 2,4-hexadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, and 1,3-heptadiene. The polymer particles further contain 0.1-20 wt.% (w.r.t. total units) of units derived from a polyfunctional ethylenically unsaturated monomer. The polymer has 50-100% gel content (G2), calculated as the component insoluble in the organic solvent. Preferred composition: The polymer particles are 0.2-80 wt.% in the binder composition (based on composition wt.). EXAMPLE - 250 pts.wt. water were added to 72 pts.wt. 2-ethylhexyl acrylate, 3 pts.wt. ethyl acrylate, 25 pts.wt. methacrylic acid, 2 pts.wt. Na dodecylbenzene sulfonate and 0.3 pt.wt. ammonium persulfate, polymerized for 8 h at 60degreesC, cooled, and 5% LiOH aq. solution added, to give a latex with pH7. To this was added N-methylpyrrolidone, and water aspirated off at 80degreesC, to give a 13 wt.% (solids) dispersion of polymer particles containing 800 ppm water. To this (to give 2 pts.wt. polymer particles) were added 2 pts.wt. ethylene-vinyl alcohol copolymer, 96 pts.wt. natural black lead and N-methylpyrrolidone, and stirred, to give a 42 wt.% (solids) slurry. The composition had 94% G1, 92% G2, gave an electrode with excellent bending properties and 41 g/cm peel strength (JIS Z1522), and gave a battery with 313 mAh/g high-temperature initial discharge capacity (after 3 cycles) and a capacity 65% of this after 50 cycles (0-1.2 V; 65degreesC), compared to 79%, 83%, excellent, 24 g/cm, 263 mAh/g and 39%, respectively, for a comparative example containing a styrene monomer.