TY - JOUR
T1 - Elucidating the role of anionic chemistry towards high-rate intermediate-temperature Na-metal halide batteries
AU - Zhan, Xiaowen
AU - Sepulveda, Jonathan P.
AU - Lu, Xiaochuan
AU - Bonnett, Jeff F.
AU - Canfield, Nathan L.
AU - Lemmon, Teresa
AU - Jung, Keeyoung
AU - Reed, David M.
AU - Sprenkle, Vincent L.
AU - Li, Guosheng
PY - 2020/1/1
Y1 - 2020/1/1
N2 - Sodium (Na)-based battery technologies that are economical (because Na is abundant) and have long cycle life are gaining importance for large-scale energy storage applications. Among the widely studied Na-based battery systems, intermediate-temperature (IT) Na-metal halide (Na-MH) batteries have demonstrated several advantages over conventional high-temperature Na batteries, including superior battery safety, lower operating temperature and manufacturing cost, potentially longer cycle life, and easier assembly. However, the rate performance of IT Na-MH batteries is inevitably affected by the lower operating temperature. In pursuit of faster charge-transfer reaction kinetics, we extended our studies of cathode materials beyond the extensively investigated NiCl2 to NiBr2 (NaBr/Ni) and NiI2 (NaI/Ni) compounds. We systematically investigated the synergetic effects of anion chemistry on the electrochemical properties. Surprisingly, among three tested cathodes, the NaBr/Ni cathode showed the highest energy density of 174 Wh/kg at 33.3 mA/cm2 (~0.8C), which is 2.5 and 1.9 times higher than those of NaCl/Ni and NaI/Ni cells. We explored the underlying enhancement mechanism in great detail via multiple structural characterization and electrochemical techniques. The sodium-halide salt dissolution in molten NaAlCl4 was found to be the determining factor in rate improvement. Our findings will greatly advance IT Na-MH battery technologies and pave the way towards fundamental understanding of reaction kinetics for high-temperature batteries in general.
AB - Sodium (Na)-based battery technologies that are economical (because Na is abundant) and have long cycle life are gaining importance for large-scale energy storage applications. Among the widely studied Na-based battery systems, intermediate-temperature (IT) Na-metal halide (Na-MH) batteries have demonstrated several advantages over conventional high-temperature Na batteries, including superior battery safety, lower operating temperature and manufacturing cost, potentially longer cycle life, and easier assembly. However, the rate performance of IT Na-MH batteries is inevitably affected by the lower operating temperature. In pursuit of faster charge-transfer reaction kinetics, we extended our studies of cathode materials beyond the extensively investigated NiCl2 to NiBr2 (NaBr/Ni) and NiI2 (NaI/Ni) compounds. We systematically investigated the synergetic effects of anion chemistry on the electrochemical properties. Surprisingly, among three tested cathodes, the NaBr/Ni cathode showed the highest energy density of 174 Wh/kg at 33.3 mA/cm2 (~0.8C), which is 2.5 and 1.9 times higher than those of NaCl/Ni and NaI/Ni cells. We explored the underlying enhancement mechanism in great detail via multiple structural characterization and electrochemical techniques. The sodium-halide salt dissolution in molten NaAlCl4 was found to be the determining factor in rate improvement. Our findings will greatly advance IT Na-MH battery technologies and pave the way towards fundamental understanding of reaction kinetics for high-temperature batteries in general.
KW - Anionic chemistry
KW - Intermediate temperature
KW - Na battery
KW - Na-metal halide battery
KW - Stationary energy storage
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U2 - 10.1016/j.ensm.2019.08.021
DO - 10.1016/j.ensm.2019.08.021
M3 - Article
SN - 2405-8297
VL - 24
SP - 177
EP - 187
JO - Energy Storage Materials
JF - Energy Storage Materials
ER -
