Ultralong K_0.5Mn_0.75PS₃ Nanowires Tailored by K-Ion Scissors for Extraordinary Sodium-Ion Storage.

Abstract

1D layered nanowires (NWs) are expected to be excellent electrode materials due to their efficient electron/ion transport and strain/stress relaxation. However, it is a great challenge to synthesize layered NWs by a top-down synthetic route. Herein, ultralong 1D layered K_0.5Mn_0.75PS₃ NWs (length: >100 µm; diameter: ≈300 nm) are synthesized for the first time using "K-ion chemical scissors", whose excellent sodium storage performance originates from the bifunctional structural unit, ingeniously combining the alloying energy storage functional unit (P-P dimer) with the quasi-intercalated functional unit ([MnS₃]^4- framework). Stress-driven K-ion scissors achieve the rapid transformation of MnPS₃ bulk to K_0.5Mn_0.75PS₃ NWs with directed tailoring. Compared to MnPS₃, the NWs exhibit enlarged interlayer spacing (9.32 Å), enhanced electronic conductivity (8.17 × 10^-5 S m^-1 vs 4.47 × 10^-10 S m^-1), and high ionic conductivity (2.14 mS cm^-1). As expected, the NWs demonstrate high capacity (709 mAh g^-1 at 0.5 A g^-1) and excellent cycling performance (≈100% capacity retention after 2500 cycles at 10 A g^-1), ranking among metal thiophosphates. A quasi-topological intercalation mechanism of the NWs is revealed through further characterizations. This work expands the top-down synthesis approach and offers innovative insights for the cost-effective and large-scale fabrication of NWs with outstanding electrochemical performance.