Professor Linda Nazar and her colleagues from the Faculty of Science at Waterloo made the important discovery, which appears in the journal, Nature Energy.
The battery uses safe, non-flammable, non-toxic materials and a pH-neutral, water-based salt. It consists of a water-based electrolyte, a pillared vanadium oxide positive electrode and an inexpensive metallic zinc negative electrode. The battery generates electricity through a reversible process called intercalation, where positively-charged zinc ions are oxidized from the zinc metal negative electrode, travel through the electrolyte and insert between the layers of vanadium oxide nanosheets in the positive electrode. This drives the flow of electrons in the external circuit, creating an electrical current. The reverse process occurs on charge.
The cell represents the first demonstration of zinc ion intercalation in a solid state material that satisfies four vital criteria: high reversibility, rate and capacity and no zinc dendrite formation. It provides more than 1,000 cycles with 80 per cent capacity retention and an estimated energy density of 450 watt-hours per litre. Lithium-ion batteries also operate by intercalation--of lithium ions--but they typically use expensive, flammable, organic electrolytes.