Abstract
We report on a new family of argyrodite lithium superionic conductors, as solid solutions Li6+xMxSb1-xS5I (M = Si, Ge, Sn), that exhibit superionic conductivity. These represent the first antimony argyrodites to date. Exploration of the series using a combination of single crystal X-ray and synchrotron/neutron powder diffraction, combined with impedance spectroscopy, reveals that an optimal degree of substitution (x), and substituent induces slight S2-/I- anion site disorder - but more importantly drives Li+ cation site disorder. The additional, delocalized Li-ion density is located in new high energy lattice sites that provide intermediate interstitial positions (local minima) for Li+ diffusion and activate concerted ion migration, leading to a low activation energy of 0.25 eV. Excellent room temperature ionic conductivity of 14.8 mS·cm-1 is exhibited for cold-pressed pellets - up to 24 mS·cm-1 for sintered pellets - among the highest values reported to date. This enables all-solid-state battery prototypes that exhibit promising properties. Furthermore, even at -78 °C, suitable bulk ionic conductivity of the electrolyte is retained (0.25 mS·cm-1). Selected thioantimonate iodides demonstrate good compatibility with Li metal, sustaining over 1000 h of Li stripping/plating at current densities up to 0.6 mA·cm-2. The significantly enhanced Li ion conduction and lowered activation energy barrier with increasing site disorder reveals an important strategy toward the development of superionic conductors.
| Original language | English |
|---|---|
| Pages (from-to) | 19002-19013 |
| Number of pages | 12 |
| Journal | Journal of the American Chemical Society |
| Volume | 141 |
| Issue number | 48 |
| DOIs | |
| State | Published - Dec 4 2019 |
Funding
This research was supported by the BASF International Scientific Network for Electrochemistry and Batteries. L.F.N. also thanks NSERC for generous support via their Canada Research Chair and Discovery Grant programs. Neutron diffraction measurement at the POWGEN instrument at Oak Ridge National Laboratory, Spallation Neutron Source, was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. We thank Dr. Melanie Kirkham for neutron powder diffraction data collection. Synchrotron XRD measurements were performed using beamline 08B1-1 at the Canadian Light Source, which is supported by the Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research. We would like to thank Dr. Joel Reid for the synchrotron X-ray powder diffraction data collection, and Professor Stefan Adams (NUS) for helpful discussions This research was supported by the BASF International Scientific Network for Electrochemistry and Batteries. L.F.N. also thanks NSERC for generous support via their Canada Research Chair and Discovery Grant programs. Neutron diffraction measurement at the POWGEN instrument at Oak Ridge National Laboratory, Spallation Neutron Source, was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. We thank Dr. Melanie Kirkham for neutron powder diffraction data collection. Synchrotron XRD measurements were performed using beamline 08B1-1 at the Canadian Light Source which is supported by the Canada Foundation for Innovation, Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan, the Government of Saskatchewan, Western Economic Diversification Canada, the National Research Council Canada, and the Canadian Institutes of Health Research. We would like to thank Dr. Joel Reid for the synchrotron X-ray powder diffraction data collection and Professor Stefan Adams (NUS) for helpful discussions
| Funders | Funder number |
|---|---|
| BASF International Scientific Network for Electrochemistry and Batteries | |
| Government of Saskatchewan | |
| Office of Basic Energy Sciences | |
| Scientific User Facilities Division | |
| US Department of Energy | |
| BASF | |
| Oak Ridge National Laboratory | |
| Canadian Light Source | |
| University of Saskatchewan | |
| Canadian Institutes of Health Research | |
| Natural Sciences and Engineering Research Council of Canada | |
| Western Economic Diversification Canada | |
| National Research Council Canada | |
| Canada Foundation for Innovation | |
| Canada Research Chairs |
