| Autor: |
Gao X; Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States., Zheng C; Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States., Shao Y; Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States., Shah VR; Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States., Jin S; Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States., Suntivich J; Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States., Joo YL; Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States. |
| Abstrakt: |
Lithium iron phosphate (LiFePO 4 , "LFP") was investigated as an additive in the cathode of lithium-sulfur (Li-S) batteries. LFP addition boosted the sulfur utilization during Li-S cycling, achieving an initial capacity of 1465 mAh/g S and a long cycle life (>300 cycles). Polysulfide adsorption experiments showed that LFP attracted polysulfides, and thus, the presence of LFP should alleviate the shuttle effect, a common failure mode. Postmortem characterization found iron phosphides, iron phosphates, and LiF in the electrode, indicating that LFP underwent dynamic reconstruction during Li-S cycling. We suspect that the formation of these species played a role in the observed performance. From the processing standpoint, adding LFP improved slurry rheology, making the preparation of a high-loading electrode more consistent. Benefiting from the high sulfur utilization and the ability to prepare electrodes with high mass loading, the S-LFP hybrid cell showed an excellent areal capacity of 2.65 mAh/cm 2 and could be stably cycled at 2 mAh/cm 2 for 250 cycles. Our results demonstrated the LFP addition as a promising strategy for realizing Li-S batteries with high sulfur loading and areal capacity. |
