However, the development of lithium sulfur batteries has been impeded by two fundamental issues which are: the low conductivity of sulfur (~10-15 S/cm)3, and the dissolution of polysulfides formed during cycling4. While the conductivity issue can be mitigated by incorporating conductive carbon into the cathode, polysulfide dissolution has proven more challenging to address5, 6. The formation and dissolution of polysulfides results in the loss of active material from the cathode which culminates in cell failure.
Previous attempts to prevent polysulfide dissolution by embedding sulfur into porous carbon structures have been moderately successful. However, the efficiency of these approaches is limited by a lack of control over porosity. To improve on these carbon structures, sulfur hosts with engineered structures and chemical properties should be developed.
In this work, lithium sulfur battery cathodes were created using complex framework materials as sulfur hosts. The cathodes were created by solution phase infiltration of sulfur into complex framework materials synthesized by microwave-assisted hydrothermal synthesis. the XRD spectrum and SEM image of one of the CFMs is shown in Figure 1. The cathodes demonstrated impressive electrochemical performance with an initial discharge capacity of ~1620 mAh/g which stabilized at 1100 mAh/g after 100 cycles.
Acknowledgement:
The authors acknowledge the financial support of DOE grant DE-EE 0006825, Edward R. Weidlein Chair Professorship funds and the Center for Complex Engineered Multifunctional Materials (CCEMM).
References:
1. F. Bidrawn, S. Lee, J. M. Vohs and R. J. Gorte, Journal of The Electrochemical Society, 2008, 155, B660-B665.
2. S. S. Zhang, Journal of Power Sources, 2013, 231, 153-162.
3. V. S. Kolosnitsyn and E. V. Karaseva, Russian Journal of Electrochemistry, 2008, 44, 506-509.
4. J.-W. Park, K. Ueno, N. Tachikawa, K. Dokko and M. Watanabe, The Journal of Physical Chemistry C, 2013, 117, 20531-20541.
5. S.-R. Chen, Y.-P. Zhai, G.-L. Xu, Y.-X. Jiang, D.-Y. Zhao, J.-T. Li, L. Huang and S.-G. Sun, Electrochimica Acta, 2011, 56, 9549-9555.
6. J. Jin, Z. Wen, G. Ma, Y. Lu and K. Rui, Solid State Ionics, 2014, 262, 170-173.