title: Retaining the 3D framework of zinc sponge anodes upon deep discharge in Zn-air cells.
abstract: We fabricate three-dimensional zinc electrodes from emulsion-cast sponges of Zn powder that are thermally treated to produce rugged monoliths. This highly conductive, 3D-wired aperiodic scaffold achieves 740 mA h gZn(-1) when discharged in primary Zn-air cells (>90% of theoretical Zn capacity). We use scanning electron microscopy and X-ray diffraction to monitor the microstructural evolution of a series of Zn sponges when oxidized in Zn-air cells to specific depths-of-discharge (20, 40, 60, 80% DOD) at a technologically relevant rate (C/40; 4-6 mA cm(-2)). The Zn sponges maintain their 3D-monolithic form factor at all DOD. The cell resistance remains low under all test conditions, indicating that an inner core of metallic Zn persists that 3D-electrically wires the electrode, even to deep DOD.
authors.affiliation: Surface Chemistry Branch, Code 6170, U.S. Naval Research Laboratory , Washington, District of Columbia 20375, United States.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Parker
authors.forename: Eric S
authors.initials: ES
authors.lastname: Nelson
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Wattendorf
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Chervin
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Long
authors.forename: Debra R
authors.initials: DR
authors.lastname: Rolison
keywords: batteries; energy; morphology; three-dimensional architecture; zinc; zinc−air