US Patent 9608272 Composition for a secondary battery cell

Composite electrode material for a rechargeable battery cell includes an electroactive material; and a polymeric binder including pendant carboxyl groups, characterized in that (i) the electroactive material includes one or more components selected from the group including an electroactive metal, an electroactive semi-metal, an electroactive ceramic material, an electroactive metalloid, an electroactive semi-conductor, an electroactive alloy of a metal, an electroactive alloy of a semi metal and an electroactive compound of a metal or a semi-metal, (ii) the polymeric binder has a molecular weight in the range 300,000 to 3,000,000 and (iii) 50 to 90% of the carboxyl groups of the polymeric binder are in the form of a metal ion carboxylate salt. A method of making a composite electrode material, an electrode, cells including electrodes and devices using such cells are also disclosed.