Compositions suitable for electrochemical cells

A composition comprising:

• (a) from 0 to less than 1% by weight of a pigment (I) having a primary particle size of from 5 nm to 100 μm which is a solid (Ia) or a compound (Ib) which acts as cathode material in electrochemical cells or a compound (Ic) which acts as anode material in electrochemical cells or a mixture of the solid (Ia) with the compound (Ib) or the compound (Ic),
• (b) more than 99 to 100% by weight of a polymeric material (II) which comprises:
• (IIa) from 1% up to, but not including 100% by weight of a polymer or copolymer (IIa ) containing reactive groups (RG) on the chain in terminal and/or lateral positions which are capable of cross linking reactions in the presence of heat and/or with UV radiation where the polymer or copolymer (IIa) contains at least one reactive group (RGa) on the chain, in terminal and/or lateral positions which is capable of hydrogen abstraction in the triplet-excited state at elevated temperature and/or with UV radiation, and contains at least one group (RGb) on the chain, in terminal and/or lateral positions which is different from (RGa) and is coreactive with (RGa), where, on average of all polymer molecules, at least one group (RGa) and one group (RGb) are present, and
• (IIb) from 99% down to, but not including 0% by weight of at least one thermoplastic and ion-conducting polymer or copolymer (IIb) which contains no reactive groups (RG).