TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The cathode is an air cathode and/or metal oxide-containing cathode. The metal oxide is chosen from manganese dioxide and vanadium pentoxide.    TECHNOLOGY FOCUS - METALLURGY - Preferred Composition: The activated metal surface does not contain passivation layer, and has fluorohydrogenate-metal species (HF-species). The metal is chosen from self-passivating metal, transition metal, noble metal, post-transition metal, base metal, poor metal, alkaline-earth metal, alkali metal, lanthanide, actinide and their alloys, preferably self-passivated metal or self-passivated metal alloy. The self-passivated metal is chosen from aluminum, chromium, titanium and tantalum, preferably aluminum. The self-passivated metal alloy is aluminum alloy and/or alloy steel. The fusion process involves melting a filler metal which is a self-passivated metal.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The fluoroanion-containing composition comprises fluorohydrogenate anion of formula: ((HF)nF)-, preferably HF2-, H2F3-, H3F4-, H4F5-, H5F6-, H6F7-, H7F8- ((HF)2.3F)-. The fluoroanion-containing composition comprises cation, room-temperature ionic liquid, solvent, ionic liquid, fluoroanion salt and additive. The cation is chosen from metal cation, inorganic cation, organic cation, polyatomic cation and organometallic cation. The metal cation is chosen from potassium ion, sodium ion, silver ion, calcium ion, magnesium ion, copper ion, ferrous ion, ferric ion, lanthanum ion, and aluminum ion. The organometallic cation is chosen from ferrocenium, alkyloctamethylferrocenium and alkylcobaltocenium. The inorganic cation is chosen from hydronium, ammonium, phosphonium, oxycation, and N-oxoammonium. The organic cation is chosen from alkylammonium, guanidinium, tert-butyl cation, choline, tropylium, alkylphosphonium, alkylated oxycation, alkylated N-oxoammonium, N,N-dialkylated imidazolium cation, N,N-dialkylated pyrrolidinium cation, N,N-dialkylated piperidinium cation, N-alkyl-pyridinium cation, 1-alkyl-3-methylimidazolium, 1-methyl-1-alkyl-pyrrolidinium, and 1-methyl-1-alkyl-piperidinium. The N,N-dialkylated imidazolium cation is chosen from dimethyl-imidazolium, 1-ethyl-3-methyl-imidazolium, 1-propyl-3-methyl-imidazolium, 1-butyl-3-methyl-imidazolium, 1-pentyl-3-methyl-imidazolium, 1-hexyl-3-methyl-imidazolium, 1-ethyl-3-propyl-imidazolium, 1-ethyl-3-butyl-imidazolium and diethyl-imidazolium. The N,N-dialkylated pyrrolidinium cation is chosen from dimethyl-pyrrolidinium, 1-ethyl-1-methyl-pyrrolidinium, 1-propyl-1-methyl-pyrrolidinium, 1-butyl-1-methyl-pyrrolidinium, 1,1-diethyl-pyrrolidinium and 1-ethyl-1-propyl-pyrrolidinium. The N,N-dialkylated piperidinium cation is chosen from dimethyl-piperidinium, 1-ethyl-1-methyl-piperidinium, 1-propyl-1-methyl-piperidinium, 1-butyl-1-methyl-piperidinium, 1,1-diethyl-piperidinium and 1-ethyl-1-propyl-piperidinium. The N-alkyl-pyridinium cation is chosen from 1-methyl-pyridinium, 1-ethyl-pyridinium, 1-propyl-pyridinium, 1-butyl-pyridinium and 1-pentyl-pyridinium. The room-temperature ionic liquid (fluoroanion-RTIL) contains organic cation chosen from 1-ethyl-3-methyl-imidazolium fluoroanion (EMIm(HF)2.3F) or 1-butyl-1-methyl-pyrrolidinium fluoroanion (Pyr14(HF)2.3F). The solvent is alkyl carbonate, ester, lactone, ether, nitrile, amide, sulfoxide, sulfone, alcohol, hydrocarbon, aromatic hydrocarbon, solid-state solvent, and miscible and/or immiscible solvent, preferably propylene carbonate, tetraglyme or dimethylsulfide. The ionic liquid is 1-ethyl-3-methyl-imidazolium bistriflimide, 1-ethyl-3-methyl-imidazolium sulfanate or 1-ethyl-3-methyl-imidazolium trifluoroimide. The fluoroanion salt is chosen from potassium dihydrogen trifluoride and potassium bifluoride. The additive is chosen from metal salt, metal oxide, thickener, gelling agent, polymer, monomer, crosslinking agent, plasticizer, diluent, humectant, surface-active agent, rheology modifier, catalyst, accelerator, inhibitor and suppressant.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The fluoroanion-containing composition is embedded in a composition-of-material comprising a liquid, polymer, biopolymer, membrane, porous matrix, gel and/or solid.