BPO4 is synthesized using a soft-chemical route. A substantial amount
of lithium can be dissolved in the BPO4 lattice, rendering solid solut
ions of xLi(2)O-BPO4 a lithium-ion-conducting electrolyte. Two synthes
es are described to form xLi(2)O-BPO4 electrolytes, one resulting in t
he formation of ultrafine powders which can be used for dynamic compac
tion.