TECHNOLOGY FOCUS - ELECTRONICS - Preferred Device: In the device (D1), an oxygen polar group of one of the polymer (p') molecule is bound to an ammonium group of one of the protein strands. The solid polymer electrolyte has an ionic conductivity that allows ions of the salt to migrate between the first electrode and second electrode. The individual carbonyl groups of one of the protein strands are bound to a cation of the salt to effect repulsion from adjacent protein strands. In the device, at least one of the protein strands has a carbonyl group; at least one of the polymer (p') molecules has a first oxygen polar group and a second oxygen polar group; a cation of the salt is bound to the first oxygen polar group of the one of the polymer molecules and to the carbonyl group of the one of the protein strands; and the second oxygen polar group of the polymer molecule is bound to an ammonium group of the protein strand.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The salt comprises at least one of LiPF6, LiTFSI, LiBF4, LiClO4, LiN(CF3SO2)2, LiAsF6, LiCF3SO3, LiI, LiBC4O8, Li(PF3(C2F5)3), LiTf, Lilm, LiBr, LiCl, LiSCN, LiTFSM, NaI, LiCF3CO2, NaBr, NaSCN, KSCN, MgCl2 and Mg(ClO4). The cations comprise Li+, K+, Na+, Ca2+, Mg2+, Cd2+, Al3+, Zn2+, Fe2+, Fe3+, Pb2+, Cu2+ and/or Ag+.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The protein comprises soy protein comprising glycinin and/or beta -conglycinin.    TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer: The conducting polymer (P1) comprises 41-49 wt.% protein, 33-40 wt.% polymer (p'), and 10-25 wt.% salt; and additionally cations non-covalently bound with the polymer (p') and/or protein. A weight ratio of the protein to the polymer (p') is 55:45. The polymer (p') molecules are 100% amorphous. The protein has a network structure of individual, at least partially unfolded protein strands, and individual molecules of the polymer (p') are entangled in the network structure of the protein. Preferred Components: The polymer (p') has a molecular weight of 200 g/mol to 8x 106 g/mol; and comprises poly(ethylene oxide). Preferred Method: The solvent is water, and has a pH. The method (M1) additionally involves heating the protein dispersion at a temperature for a period prior to mixing with polymer (p'); adjusting at least one of the pH of solvent, temperature, or period based on at least one of target electrical conductivity or targeted mechanical flexibility of the solid-state conductor; and adjusting at least one of ratio between the polymer and protein (p'), or a composition of the protein (p'), based on at least one of target electrical conductivity or target mechanical flexibility of the solid-state conductor. The protein includes protein strands in a coiled structure, where the heating step involves substantially unfolding the protein strands in the coiled structure to form a network structure of individual, at least partially unfolded protein strands. The adjusting step involves adjusting the pH of solvent, temperature, or period to substantially unfold the protein strands in the coiled structure. When the protein includes protein strands, then the method (M1) involves forming network structure of individual, at least partially unfolded protein strands; and evaporating the solvent to form solid-state conductor having the entangled in the network structure of the protein. EXAMPLE - No suitable example given.