two electrodes electrically connected to a mixture of said electrolyte and said electrolyte solution, and insulated from each other, wherein one of said electrodes is made of {HEAD ~ a material} selected from {TAIL ~ the group} consisting of manganese oxide , zinc oxide , and magnesium oxide , and the other of said electrodes contains graphite 
selected from
two electrodes electrically connected to a mixture of said electrolyte and said electrolyte solution , and insulated from each other , wherein one of said electrodes is made of { HEAD ~ a material } selected from { TAIL ~ the group } consisting of manganese oxide , zinc oxide , and magnesium oxide , and the other of said electrodes contains graphite
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH