Architectural engineering of metal-organic framework-derived hierarchical hydrangea-like NiPS3/C for superior sodium-ion storage.

Abstract

Two-dimensional (2D) layered NiPS₃ has drawn considerable attention as a promising anode candidate for alkali-ion batteries, boasting tunable electronic configurations and high theoretical capacity (∼1296.8mAh g^-1). However, two fundamental challenges impede its practical application: irreversible nanosheet restacking during synthesis seriously compromising Na⁺ ion diffusion, and structural collapse during cycling causing catastrophic capacity fade. Addressing these limitations, we proposed a metal-organic framework (MOF)-mediated structural transformation strategy to construct hierarchical hydrangea-like NiPS₃/C microspheres through carbonization and phospho‑sulfurization of Ni-BPDC (BPDC = 4,4'-biphenyldicarboxylic) precursor. The unique architecture manifested multiple advantageous features: (i) randomly oriented NiPS₃ nanosheets ensuring abundant electrochemical active sites and efficient electrolyte permeation; (ii) interconnecting conductive carbon networks enabling ultrafast electron transport; and (iii) spatially distributed carbon nanoparticles helping accommodate volume changes. Benefiting from these synergistic effects, the developed NiPS₃/C electrode delivered outstanding electrochemical performance, including high specific capacity (1107.8 mAh g^-1 at 0.1 A g^-1) and superb cycling stability (98.2% capacity retention after 1000 cycles at 5.0 A g^-1). Through in-situ/ex-situ structure diagnostics, we decoded the dynamic phase evolution during sodiation/desodiation, revealing a conversion-alloying mechanism. This work established a general strategy for designing high-performance MOF-derived anode materials for energy storage systems.