%0 Journal Article
%T On the Origin and Implications of Li$_2$O$_2$ Toroid Formation in Nonaqueous Li-O$_2$ Batteries
%A Nagaphani B. Aetukuri
%A Bryan D. McCloskey
%A Jeannette M. Garc¨Şa
%A Leslie E. Krupp
%A Venkatasubramanian Viswanathan
%A Alan C. Luntz
%J Physics
%D 2014
%I arXiv
%R 10.1038/nchem.2132
%X The lithium-air (Li-O$_2$) battery has received enormous attention as a possible alternative to current state-of-the-art rechargeable Li-ion batteries given their high theoretical specific energy. However, the maximum discharge capacity in nonaqueous Li-O$_2$ batteries is limited to a small fraction of its theoretical value due to the insulating nature of lithium peroxide, Li$_2$O$_2$, the battery$'$s primary discharge product. In this work, we show that the inclusion of trace amounts of electrolyte additives, such as H$_2$O, significantly improve the capacity of the Li-O$_2$ battery. These additives trigger a solution-based growth mechanism due to their solvating properties, thereby circumventing the Li$_2$O$_2$ conductivity limitation. Experimental observations and a growth model imply that this solution mechanism is responsible for Li$_2$ toroid formation. We present a general formalism describing an additive$'$s tendency to trigger the solution process, providing a rational design route for electrolytes that afford larger Li-air battery capacities.
%U http://arxiv.org/abs/1406.3335v1