Archer group publishes on stabilizing electrochemical interfaces in Nature Energy
The future of electrochemical energy storage in rechargeable batteries is thought to hinge on the advancement of science and technology that enable rechargeable batteries that utilize reactive metals, such as lithium, sodium, and aluminum as anodes. With specific capacity more than ten-times that of LiC6 used as the anode in today’s lithium-ion battery technology, the Li-metal anode has for instance been under intense scrutiny by research teams world-wide because it is understood to be critical for enabling several next-generation electrochemical storage technologies, including Li-Sulfur and Li-Air batteries, which offer competitive energy storage with fossil fuels. Multiple difficult challenges — parasitic reactions of the metal with liquid electrolytes, unstable/dendritic electro-deposition, and dendrite-induced short circuits derailed early efforts to commercialize such lithium-metal batteries (LMBs). Over extended cycles of charge and discharge, unstable deposition produce tree-like, diffusion-limited structures termed dendrites, which grow from the metal surface and ultimately bridge the inter-electrode space, short-circuiting the cell. In a typical volatile electrolyte, the ohmic heat generated by such shorts lead to thermal run-away events and poses significant risks for battery fire and explosion. These challenges are shared by battery technologies based on earth abundant metals such as sodium and aluminum. In their paper titled “Design principles for electrolytes and interfaces for stable lithium-metal batteries” (http://www.nature.com/articles/nenergy2016114) Archer and his students (Mukul Tikekar, Snehashis Choudhury and Zhengyuan Tu) report on the principles that underpin stability of electrodes based on lithium and other reactive metals. They also disclose a universal state diagram that practitioners in the field can use to design electrodes, electrolytes, and cell operating conditions to ensure stable battery operations.