Lithium-Air Battery Gets A Safety Boost

The safety of lithium-air batteries can be improved by replacing the commonly used metallic lithium anode with one made from a lithiated silicon-carbon composite, according to an international research team (Nano Lett., DOI: 10.1021/nl303087j). The relatively large amount of energy released by lithium oxidation and the potential for packaging that energy in small, lightweight cells that are 10 times more powerful than lithium-ion batteries have made lithium-air batteries a hot topic of research for electric vehicles. However, large-scale development of these batteries has been hampered, in part because the standard reactive lithium-metal anode is prone to forming hazardous dendrites that grow during charge cycling. The dendrites can pierce the anode-cathode separator and suddenly short out the battery. Bruno Scro­sati and Jusef Hassoun of Sapienza University of Rome and coworkers synthesized a dendrite-resistant composite consisting of nanosized dots of lithiated silicon embedded in microsized carbon particles. Tests show that the new cells exhibit reduced voltage and charge capacity compared with standard lithium-air batteries, yet those parameters remained largely stable over 15 charge-discharge cycles.