Ultrastable and high-performance 3D core-shell NiCo2S4@Bi2O3 nanorod arrays as anode for Li S batteries

In spite of the low specific capacity of Bi2O3 (∼386 mA h g−1), it lies among auspicious contenders to be utilized as anode for future generation lithium-ion batteries (LIBs). Conversely, the persistently low valued capacity is causing the restrictions on its superb anticipated electro-chemical properties and obscuring their useful applications/devices. Similarly bimetallic transition metal sulfides with superior electro-chemical performances have gained the attention due to the existence of synergistic effect among bimetallic cations. Herein, a novel template-assisted, two-step hydrothermal method followed by electrodeposition technique is employed to fabricate hybrid 3D core-shell NiCo2S4@Bi2O3 nanorod arrays (NRAs). The fabricated hybrid-structure comprises the qualities of both materials; NiCo2S4 presents the backbone for structural stability, while Bi2O3 provides the high specific capacity. Hybrid core-shell structure has provided the integrating facile strain relaxation, along with the fast electron and ion transport. Hybrid 3D core-shell NiCo2S4@Bi2O3 NRAs with the possession of high Bi2O3 mass loading has exhibited the excellent capacity of ∼2344 mA h g−1 with a columbic efficiency of 96 %, which is much improved compare to pristine NiCo2S4 NRAs (∼1865 mA h g−1) with columbic efficiency of 89 % and Bi2O3 nanosheet arrays (∼1160 mA h g−1) with columbic efficiency of 54 % respectively, demonstrating that hybrid 3D core-shell NiCo2S4@Bi2O3 NRAs have presented decent rate capability at current density 0.4 A g−1 and particularly significant cycle stability (∼1930 mA h g−1) even after 100 successive cycles. Achieved outcomes not only highlight the innovative opportunity for novel core-shell formation, but also provide the vision of rational design for innovative electrode materials for LIBs.