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Two-dimensional (2D) materials have been developed intensively over the last decade, and combining different 2D materials to form heterogeneous 2D materials is anticipated to be more attractive with broader applications. The precise evaluation and prediction of interfacial properties of 2D heterostructures are critical for designing more robust heterostructures and developing advanced, engineered molecular devices. Here, we present a brief review on experimental (namely, atomic force microscopy (AFM), in situpeel test, double cantilever beam, pressurized blister test and sheet-on-bead method) and theoretical techniques (namely, molecular dynamics and density functional theory) for probing the adhesion/interaction energy of the interface of 2D heterogeneous materials and paving the way for future applications.

We reported a controlled synthesis method to obtained carbon spheres with tunable geometry under low ZnCl2aqueous solution conditions using polytriazine as a precursor. The polytriazine precursor was polymerized by mixing/reaction of 2,6-diaminopyridine and formaldehyde in the presence of a diluted ZnCl2aqueous system. The obtained nanospheres were then decomposed to adulterate nitrogen porous carbon nanospheres (N-PCNSs) by the decomposition and blistering process at high temperature by degrees. ZnCl2worked as a solid-template and played the role of a stabilizing and foaming agent in the reaction. The as-prepared N-PCNSs with controllable spherical geometry, large micro-/mesoporous volume and high nitrogen content (∼8.5 wt %) were employed in electric double-layer capacitors that have a good specific capacitance (636 F/g at 1 A/g) and are long lasting. Besides, the N-PCNS delivered a high energy density of 22.1 Wh/Kg at a power density of 500 W/kg.

In response to the increasing concern for energy management, molybdenum disulfide (MoS2) has been extensively researched as an attractive anode material for sodium-ion batteries (SIBs). The proficient cycling durability and good rate performance of SIBs are the two key parameters that determine their potential for practical use. In this study, nature-inspired three-dimensional (3D) MoS2ultrathin marigold flower-like microstructures were prepared by a controlled hydrothermal method. These microscale flowers are constructed by arbitrarily arranged but closely interconnected two-dimensional ultrathin MoS2nanosheets. The as-prepared MoS2microflowers (MFs) have then been chemically wrapped by layered graphene sheets to form the bonded 3D hybrid MoS2-G networks. TEM, SEM, XRD, XPS, and Raman characterizations were used to study the morphology, crystallization, chemical compositions, and wrapping contact between MoS2and graphene. The ultrathin nature of MoS2in 3D MFs and graphene wrapping provide strong electrical conductive channels and conductive networks in an electrode. Benefitting from the 2 nm ultrathin crystalline MoS2sheets, chemically bonded graphene, defect-induced sodium storage active sites, and 3D interstitial spaces, the prepared electrode exhibited an outstanding specific capacity (606 mA h g–1at 200 mA g–1), remarkable rate performance (345 mA h g–1at 1600 mA g–1), and long cycle life (over 100 cycles with tremendous Coulombic efficiencies beyond 100%). The proposed synthesis strategy and 3D design developed in the present study reveal a unique way to fabricate promising anode materials for SIBs.

Low cycling stability and poor rate performance are two of the distinctive drawbacks of most electrode materials for sodium-ion batteries (SIBs). Here, inspired by natural flower structures, we take advantage of the three-dimensional (3D) hierarchical flower-like stable microstructures formed by two-dimensional (2D) nanosheets to solve these problems. By precise control of the hydrothermal synthesis conditions, a novel three-dimensional (3D) flower-like architecture consisting of 2D Na2Ti3O7nanosheets (Na-TNSs) has been successfully synthesized. The arbitrarily arranged but closely interlinked thin nanosheets in carnation-shaped 3D Na2Ti3O7microflowers (Na-TMFs) originate a good network of electrically conductive paths in an electrode. Thus, Na-TMFs can get electrons from all directions and be fully utilized for sodium-ion insertion and extraction reactions, which can improve sodium storage properties with enhanced rate capability and super cycling performance. Furthermore, the large specific surface area provides a high capacity, which can be ascribed to the pseudo-capacitance effect. The wettability of the electrolyte was also improved by the porous and crumpled structure. The remarkably improved cycling performance and rate capability of Na-TMFs make a captivating case for its development as an advanced anode material for SIBs.