Unique Flexible NiFe₂O₄@S/rGO-CNT Electrode via the Synergistic Adsorption/Electrocatalysis Effect toward...

A unique flexible NiFe₂O₄ hollow sphere@S/rGO-CNT (NiFe₂O₄@S/C) cathode was rationally designed and synthesized to tackle the issues of lithium-sulfur batteries. In this strategy, the introduced rGO and CNTs offer a flexible and conductive skeleton to facilitate the transport of electrons and/or ions and a physical barrier to confine polysulfides. Furthermore, as an efficient sulfur host, NiFe₂O₄ hollow spheres can further absorb the soluble polysulfides by strong chemical interaction due to their intrinsic polarity and also serve as a catalyst to promote the redox kinetics of polysulfide conversion. Benefiting from the synergism of the physical confinement, polar chemical adsorption, and catalytic conversion, the as-prepared flexible NiFe₂O₄@S/C electrode delivers a high initial capacity of 1193 mAh g^-1 at 100 mA g^-1 and excellent long-term cycling stability up to 500 cycles with a low decay rate of 0.059% per cycle at 500 mA g^-1.