Higher Capacity Lithium-Ion Battery

A novel lithium-ion battery design that includes tin, sulfur, and a polymer outperforms today's commercial units in terms of charge-storage capacity, according to chemists in Italy who designed the device (Angew. Chem. Int. Ed., DOI: 10.1002/anie.200907324). For years, researchers have known that lithium-sulfur-based batteries are capable of packing more power per size and weight than commercial batteries made with lithium/transition-metal oxide cathodes and carbon-based anodes. Yet progress in developing suitably safe, stable, and long-lasting versions of the lithium-sulfur devices has been plagued by unwanted reactions that decompose the organic liquid electrolyte, form polysulfides (Li₂S _x ), and foul metallic lithium electrodes. Jusef Hassoun and Bruno Scrosati of the University of Rome have devised a way to sidestep those problems. The team created a battery with a carbon/lithium sulfide cathode, a tin/carbon nanocomposite anode, and a polyethylene oxide/lithium trifluoromethanesulfonate gel-type membrane to confine and prevent decomposition of the electrolyte. The battery exhibited a capacity of 1.1 kWh/kg, a record for a battery lacking a metallic lithium electrode, and remained stable for dozens of charge cycles conducted over the course of several days, the team reports.