Search

In this work, we have developed a simple and facile method to synchronously synthesize hollow FeSe2/C nanospheres using the Kirkendall effect. When evaluated as an anode for SIBs, the hollow FeSe2/C nanospheres exhibit a high discharge capacity retention of 474.1 mA h g−1 at 0.05 A g−1 (based on the calculation of FeSe2), which is very close to the theoretical capacity of FeSe2 (∼500 mA h g−1). Meanwhile, hollow FeSe2/C also has a superior rate capability of 364.5 and 316.5 mA h g−1 even at 2.0 and 5.0 A g−1, respectively. The high performance of the hollow FeSe2/C nanospheres can be ascribed to the unique carbon coated hollow nanostructure. [ABSTRACT FROM AUTHOR]

The insulating and dissoluble features of sulfur and polysulfide intermediates significantly hinder the cycling performance and coulombic efficiency of Li-S batteries. We herein design fully integrated hierarchical double-shelled Co 9 S 8 @CNT hollow nanospheres as a sulfur host, where each shell owns a tri-layer sandwich structure and six functional layers are constructed in total. Uniquely, the hierarchical structures integrate the beneficial functions of electrical conductivity, ion diffusion, polysulfide immobilization and polysulfide redox kinetics. The Co 9 S 8 @CNT/S delivers a reversible specific capacity of 1415 mA h g -1 at 0.2C, which is very close to the theoretical capacity of sulfur. Moreover, even at a high rate of 10C, an unprecedented capacity of 676.7 mA h g -1 can still be achieved, which represents the best rate capability among the ever-reported sulfur cathodes with similar sulfur content. More importantly, the Co 9 S 8 @CNT/S also displays a high coulombic efficiency of nearly 100% and an excellent cycling performance for up to 1000 cycles with a capacity fading rate of only 0.0448% per cycle. Even at the loading amount of 5.5 mg cm -2 , the areal capacity can still reach 4.3 mA h cm -2 . The concept to rationally integrate distinct components into fully functional units could provide valuable insights for the development of Li-S batteries and beyond.

In this work, we have developed a simple and facile method to synchronously synthesize hollow FeSe2/C nanospheres using the Kirkendall effect. When evaluated as an anode for SIBs, the hollow FeSe2/C nanospheres exhibit a high discharge capacity retention of 474.1 mA h g-1 at 0.05 A g-1 (based on the calculation of FeSe2), which is very close to the theoretical capacity of FeSe2 (∼500 mA h g-1). Meanwhile, hollow FeSe2/C also has a superior rate capability of 364.5 and 316.5 mA h g-1 even at 2.0 and 5.0 A g-1, respectively. The high performance of the hollow FeSe2/C nanospheres can be ascribed to the unique carbon coated hollow nanostructure.