TECHNOLOGY FOCUS - ELECTRONICS - Preferred Cathode: The cathode further comprises a current collector in electrical communication with the material or combination of materials. Preferred Device: The device has a specific energy of at least 200 Wh/kg when measured at 60 degrees C and a current of at least 100 mA/g of active cathode material. The anode, electrolyte, and cathode, together comprise a stack of 1-500 mu m thickness. Preferred Method: Preparing the electrochemically active material or combination of electrochemically active materials involves a physical vapor deposition technique or a chemical vapor deposition technique; precipitating from a solution; depositing a layer of the material or materials to a thickness of 10-300 mu m on a substrate.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compound: The compound (I) has a discharge capacity of at least 400 mAh/g, an average discharge voltage of at least 2 volts or an average hysteresis of at most 2 volts, when discharged from 1-4.5 volt versus the lithium metal electrode, and when discharged at a rate of at least 100 mA/g and at 40-120 degrees C. The compound (I) and lithium ions can undergo a reaction to produce the iron metal, and the lithium fluoride, oxide, and/or sulfide, and where the reaction has a Gibbs free energy 500 kJ/mol. Preferred Material: The electrochemically active material or combination of electrochemically active materials has a specific capacity of at least 300 mAh/g above a voltage of at least 2.5 volts relative to lithium, when charged to a voltage of 3.9 volts relative to lithium and discharged at a rate of at least 100 mA/g and at 40-120 degrees C. The electrochemically active material or combination of electrochemically active materials has a specific capacity of at least 500 mAh/g above a voltage of at least 1 volt relative to lithium, when charged to a voltage of 3.9 volts relative to lithium and discharged at a rate of at least 100 mA/g and at 40-120 degrees C. The electrochemically active material or combination of electrochemically active materials has a specific energy of at least 600 mWh/g above a voltage of at least 2.9 volts relative to lithium, when charged to a voltage of 3.9 volts relative to lithium and discharged at a rate of at least 100 mA/g and at 40-120 degrees C. The electrochemically active material or combination of electrochemically active materials has a specific energy of at least 1000 mWh/g above a voltage of at least 1 volt relative to lithium, when charged to a voltage of 3.9 volts relative to lithium and discharged at a rate of at least 100 mA/g and at a temperature of 40-120 degrees C. The electrochemically active material or combination of electrochemically active materials comprises particles having a median characteristic dimension of 10-10000 nm. Preferred Component: The current collector comprises copper, copper alloy, nickel, steel, stainless steel, aluminum, carbon-coated aluminum or aluminum alloy. Preferred Definitions:    a=1-5;    b=0-2;    c=0-1.5.    EXAMPLE - No suitable example given.