Hierarchical wormlike engineering: Self-assembled SnS2 nanoflake arrays decorated on hexagonal FeS2@C nano-spindles enables stable and fast sodium storage

The exploitation of advanced electrode materials with an unique hierarchical architecture and physicochemical feature undertakes an extremely prominent role in achieving rapid ion-transport and remarkable performance to further promote the development of highly efficient sodium-ion batteries (SIBs). Herein, a multi-step synthesis tactic involving in-situ polymerization of dopamine, high-temperature sulfuration and subsequent solvothermal was put forward for the construction of exquisitely hierarchical wormlike architecture by growing SnS2 nano -flake arrays on hexagonal FeS2@C nano-spindles (FeS2@C@SnS2) utilizing tailor-made Fe-based metal-organic framework nanorod as an initial template. The experimental results combined with theoretical analysis thor-oughly disclose that the successful construction of the hierarchical wormlike FeS2@C@SnS2 architecture can markedly afford sufficient active reaction sites and favorable Na+ adsorption, as well as accelerate ion-diffusion kinetics and enhance surface-capacitive contribution, thereby synergistically making its higher initial coulombic efficiency, more outstanding cycling capability and rate performance than FeS2@C and SnS2 samples. Specif-ically, the FeS2@C@SnS2 composite delivers an attractive reversible capacity up to 585.7 mAh g-1 over 1000 cycles at 1.0 A g-1, outstanding high-rate, and durable sodium storage features (only 0.07 % capacity fading each cycle over 2800 cycles at 20.0 A g-1). Moreover, ex-situ experimental characterizations systematically unravel the FeS2@C@SnS2 experiences phase transformations of preliminarily proceeding with the Na+ insertion, fol-lowed by the conversion and further alloying-dealloying reaction mechanism. Prompted by the above advan-tages, the FeS2@C@SnS2||Na3V2(PO4)3@C full cell presents its potential application feasibility toward SIBs, achieving good cycling performance and seductive specific capacity.