Introduction

Large-scale energy storage systems that enable renewable integration and grid stability demand electrode materials with high capacity, long cycle life, and fast reaction kinetics [1–3]. Among various emerging candidates, layered transition-metal dichalcogenides (LTMDs), notably molybdenum disulfide (MoS2), have attracted considerable attention as anode materials because of their rich intercalation/conversion chemistry and high theoretical capacity of ~ 670 mAh g−1 for lithium-ion batteries (LIBs) [4]. However, the practical application of MoS2 is still limited by severe structural degradation during repeated lithiation/delithiation processes [5]. In addition, the intrinsically low electronic conductivity of semiconducting MoS2 restricts charge-transfer kinetics and rate performance [6].

To mitigate these problems, extensive efforts have focused on morphology engineering [7], heteroatom doping [8, 9], and carbon hybridization [10, 11]. Compositing MoS2 with conductive carbon materials effectively improves electron transport and buffers volume changes, while further pore engineering and few-layer architectures promote Li+ accessibility [12, 13]. Nevertheless, most reported nanocomposites rely on weak physical contacts or simple surface coatings, which often leads to interfacial detachment, interlayer collapse, and progressive degradation during long-term cycling [14, 15]. As a result, in physical MoS2 and carbon hybrids (MoS2/C), MoS2 often undergoes slow Li+ transport and incomplete conversion reactions during lithiation. The formation of poorly conductive Li2S and electrochemically inactive (“dead”) Mo further impedes the reverse conversion process during delithiation, thereby causing severe structural degradation and rapid capacity decay during cycling (Scheme 1a). Moreover, multilayer MoS2 with MoS2/MoS2 interfaces is prone to pulverization after repeated cycling, which further deteriorates electrochemical reversibility.

Scheme 1: Schematics of a physical MoS2/C hybrids and b the proposed nitrogen-bridged MoS2/C heterostructures for electrochemical Li+ storage and their structure evolution during cycling

Interfacial engineering that creates strong chemical bonds, such as Mo–N or Mo–C, between MoS2 and carbon offers a promising route to reconcile electronic conductivity, structural integrity, and reversible electrochemistry. Recent approaches, including heteroatom-doped carbons [16, 17], single-atom bridges [18, 19], and engineered 2D superlattices [20, 21], have demonstrated that interfacial chemistry and stacking configurations critically govern reaction kinetics and cycling durability. However, these approaches often require additional reagents and complex synthetic routes, raising concerns regarding cost and scalability [22]. Moreover, insufficient interlayer spacing caused by weak interfacial interactions continues to hinder Li⁺ diffusion kinetics in many existing systems [23, 24].

Herein, we introduce a quaternary ammonium surfactant-mediated strategy to construct porous MoS2/C heterostructures with interfacial Mo–N bridges, thereby improving the conversion reversibility of MoS2 during lithiation/delithiation. The Mo–N bridges serve not only as efficient electron-transfer pathways but also as robust structural anchors that preserve electrode integrity during cycling. The resulting N-bridged MoS2 and carbon heterostructure (denoted as MoS2–N–C) provides strong interfacial interaction and expanded interlayer spacing, thereby accelerating electron transfer and Li⁺ diffusion and converting into reversible Mo species for excellent cycling stability (Scheme 1b). Remarkably, the optimized MoS2–N–C700 heterostructure achieves ~ 100% capacity retention after 800 cycles at 0.5 A g−1 for LIBs. Moreover, when paired with activated carbon (AC) in lithium-ion supercapacitors (LISCs), it exhibits high power density and stable cycling for over 10,000 cycles at 1 A g−1, underscoring its strong potential as a next-generation high-performance anode material. This work demonstrates a scalable molecular-level strategy to construct chemically coupled LTMD/C heterostructures toward electrochemical energy storage systems.