The phase-controlled synthesis of metallic and ambient-stable 2D MX 2 (M is Mo or W; X is S) with 1T octahedral coordination will endow these materials with superior performance compared with their semiconducting 2H coordination counterparts. We report a clean and facile route to prepare 1T-MoS 2 and 1T-WS 2 through hydrothermal processing under high magnetic fields. We reveal that the as-synthesized 1T-MoS 2 and 1T-WS 2 are ambient-stable for more than 1 year. Electrochemical measurements show that 1T-MoS 2 performs much better than 2H-MoS 2 as the anode for sodium ion batteries. These results can provide a clean and facile method to prepare ambientstable 1T-phase MX 2 .

2D/2D heterostructures can combine the collective advantages of each 2D material and even show improved properties from synergistic effects. 2D Transition metal carbide Ti 3 C 2 MXene and 2D 1T-MoS 2 have emerged as attractive prototypes in electrochemistry due to their rich properties. Construction of these two 2D materials, as well as investigation about synergistic effects, is absent due to the instability of 1T-MoS 2 . Here, 3D interconnected networks of 1T-MoS 2 /Ti 3 C 2 MXene heterostructure are constructed by magneto-hydrothermal synthesis, and the electrochemical storage mechanisms are investigated. Improved extra capacitance is observed due to enlarged ion storage space from a synergistically interplayed effect in 3D interconnected networks. Outstanding rate performance is realized because of ultrafast electron transport originating from Ti 3 C 2 MXene. This work provides an archetype to realize excellent electrochemical properties in 2D/2D heterostructures.