Phase‐Engineered 1T/2H‐WS 2 Heterostructures in Hybrid Carbon Networks for High‐Rate and Durable Sodium‐Ion Storage
Atin Pramanik, Shilpi Sengupta, Juan Gomez Quispe, Xi Chen, Anmol Dubey, Maryam Amiri, Tanguy Terlier, Pedro Alves da Silva Autreto, Pulickel M. Ajayan, Manab KunduABSTRACT
Metallic 1T transition‐metal dichalcogenides are promising for sodium‐ion storage because of their higher electrical conductivity and faster ion transport than semiconducting 2H counterparts, yet stabilizing the 1T phase remains challenging. Here, we report phase‐engineered WS 2 /hybrid‐carbon nanocomposites prepared by lithium‐assisted exfoliation and freeze‐drying, delivering a high‐performance sodium‐ion battery (SIB) anode. Integration of reduced graphene oxide and multiwalled carbon nanotubes (rGO and MWCNTs) induces partial phase conversion (2H→1T) in WS 2 and yields a stabilized 1T/2H mixed‐phase architecture within a conductive carbon network. Structural and spectroscopic analyses support the coexistence of 1T and 2H domains and reveal strong interfacial coupling with the carbon scaffold, thereby enhancing electrical conductivity, suppressing nanosheet restacking, and improving structural stability. As a result, the 1T/2H‐WS 2 @rGO/MWCNTs composite delivers a reversible capacity of ∼500 mAh/g at 25 mA/g, excellent rate capability up to 5 A/g, and long‐term cycling stability over 1000 cycles with negligible capacity decay, ∼99.2% capacity retention, together with strong full‐cell performance when paired with NaFePO 4 . First‐principles calculations further reveal stronger Na adsorption and a wider thermodynamically stable sodiation window for 1T‐WS 2 than for 2H‐WS 2 . These results highlight the combination of phase‐engineering and conductive carbon‐scaffolding as an effective strategy for developing fast and durable WS 2 ‐based anodes for SIBs.