Cathode architectures for alkali metal / oxygen batteries

摘要

Electrochemical energy storage devices, such as alkali metal-oxygen battery cells (e.g., non-aqueous lithium-air cells), have a cathode architecture with a porous structure and pore composition that is tailored to improve cell performance, especially as it pertains to one or more of the discharge/charge rate, cycle life, and delivered ampere-hour capacity. A porous cathode architecture having a pore volume that is derived from pores of varying radii wherein the pore size distribution is tailored as a function of the architecture thickness is one way to achieve one or more of the aforementioned cell performance improvements.

主权项

1. An alkali metal oxygen battery cell comprising:
an alkali metal anode having a major active surface; and a porous cathode architecture adjacent the anode major active surface, the architecture comprising first and second porous regions each having a different entirely wettable porous structure and further comprising a certain volume of liquid electrolyte; wherein the first porous region provides active surface sites for electron transfer, access for molecular oxygen to enter the cathode architecture, and is characterized as having a first region total pore volume; the second porous region, not an electron transfer region, is: i) in pore communication with the first porous region; ii) disposed adjacent to the anode major surface; and iii) characterized as having a second region total pore volume; and the certain volume of liquid electrolyte is greater than the total pore volume of the second region but less than the cumulative total pore volumes of the first and second regions, and said certain volume of liquid electrolyte is the amount present in the architecture immediately prior to and upon initial cell operation.