Affiliation:
1. Materials Science and Engineering Program & Texas Materials Institute (TMI) The University of Texas at Austin Austin TX 78712–1591 USA
2. School of Mechanical Engineering Purdue University West Lafayette IN 47907 USA
3. Center for Integrated Nanotechnologies Los Alamos National Laboratory Los Alamos NM 87545 USA
Abstract
AbstractAluminum oxide (Al2O3) nanopowder is spin‐coated onto both sides of commercial polypropene separator to create artificial solid‐electrolyte interphase (SEI) and artificial cathode electrolyte interface (CEI) in potassium metal batteries (KMBs). This significantly enhances the stability, including of KMBs with Prussian Blue (PB) cathodes. For example, symmetric cells are stable after 1,000 cycles at 0.5 mA/cm2–0.5 mAh/cm2 and 3.0 mA/cm2–0.5 mAh/cm2. Alumina modified separators promote electrolyte wetting and increase ionic conductivity (0.59 vs. 0.2 mS/cm) and transference number (0.81 vs. 0.23). Cryo‐stage focused ion beam (cryo‐FIB) analysis of cycled modified anode demonstrates dense and planar electrodeposits, versus unmodified baseline consisting of metal filaments (dendrites) interspersed with pores and SEI. Alumina‐modified CEI also suppresses elemental Fe crossover and reduces cathode cracking. Mesoscale modeling of metal – SEI interactions captures crucial role of intrinsic heterogeneities, illustrating how artificial SEI affects reaction current distribution, conductivity and morphological stability.
Funder
Office of Fossil Energy and Carbon Management