Thin-film rechargeable lithium batteries with amorphous Li{sub x}Mn{sub 2}O{sub 4} cathodes

Cathode films of amorphous Li{sub x}Mn{sub 2}O{sub 4} have been grown by rf magnetron sputtering on unheated substrates. A low process gas pressure and a positive substrate bias were found to give the most conductive cathodes. The batteries were completed with subsequent deposition of a lithium phosphorous oxynitride electrolyte and Li anode. These cells were cycled at 25-100 C between 4.5 and 1.5 V which corresponds to {approximately}0 to 2 Li per Mn{sub 2}O{sub 4}. The amorphous cathodes have a highs pecific capacity and a low capacity loss per cycle