The growing interest in the development of next-generation net zero energy systems has led to the expansion of molybdenum disulfide (MoS 2 ) research in this area. This activity has resulted in a wide range of manufacturing/synthesis methods, controllable morphologies, diverse carbonaceous composite structures, a multitude of applicable characterization techniques, and multiple energy applications for MoS 2 . To assess the literature trends, 37,347 MoS 2 research articles from Web of Science were text scanned to classify articles according to energy application research and characterization techniques employed. Within the review, characterization techniques are grouped under the following categories: morphology, crystal structure, composition, and chemistry. The most common characterization techniques identified through text scanning are recommended as the base fingerprint for MoS 2 samples. These include: scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Similarly, XPS and Raman spectroscopy are suggested for 2H or 1T MoS 2 phase confirmation. We provide guidance on the collection and presentation of MoS 2 characterization data. This includes how to effectively combine multiple characterization techniques, considering the sample area probed by each technique and their statistical significance, and the benefit of using reference samples. For ease of access for future experimental comparison, key numeric MoS 2 characterization values are tabulated and major literature discrepancies or currently debated characterization disputes are highlighted.

The relative vast abundance and more equitable global distribution of terrestrial sodium makes sodium-ion batteries (NIBs) potentially cheaper and more sustainable alternatives to commercial lithium-ion batteries (LIBs). However, the practical capacities and cycle lives of NIBs at present do not match those of LIBs and have therefore hindered their progress to commercialisation. The present drawback of NIB technology stems largely from the electrode materials and their associated Na+ ion storage mechanisms. Increased understanding of the electrochemical storage mechanisms and kinetics is therefore vital for the development of current and novel materials to realise the commercial NIB. In contrast to x-ray techniques, the non-dependency of neutron scattering on the atomic number of elements (Z) can substantially increase the scattering contrast of small elements such as sodium and carbon, making neutron techniques powerful for the investigation of NIB electrode materials. Moreover, neutrons are far more penetrating which enables more complex sample environments including in situ and operando studies. Here, we introduce the theory of, and review the use of, neutron diffraction and quasi-elastic neutron scattering, to investigate the structural and dynamic properties of electrode and electrolyte materials for NIBs. To improve our understanding of the actual sodium storage mechanisms and identify intermediate stages during charge/discharge, ex situ, in situ, and operando neutron experiments are required. However, to date there are few studies where operando experiments are conducted during electrochemical cycling. This highlights an opportunity for research to elucidate the operating mechanisms within NIB materials that are under much debate at present.

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With the constant rise of consumer demands for energy storage devices, improvements in current Li-ion battery (LIB) technology are paramount. At present, graphite is the most common commercial anode material, with a theoretical capacity of 372 mA h g-1. However, it is inevitable that graphite alone will no longer suffice to meet large capacity and high power requirements. Transition metal dichalcogenides (TMDs) are isostructural analogues of graphite where a transition metal layer is sandwiched between two chalcogen layers by strong intraplanar bonds while each unit is stacked together through weak van der Waal’s interplanar forces. MoS2 is a TMD which has also been considered as a potential candidate for LIB anodes as its theoretical capacity (670 mA h g-1) is almost double that of graphite. Unfortunately, the anode’s practical performance is very poor due to large volume expansion upon charging/discharging and formation of undesirable polysulphides. Combining MoS2 and graphite could generate an alternating layer heterostructure that exploits the desirable properties of each material. Most syntheses of MoS2/Graphite heterostructures in the literature either require extensive reaction conditions such as long periods of ultrasonication, or produce very low yields such as chemical vapour deposition. Additionally, ultrasonication often introduces many undesirable defects, due to the solvent used and harsh conditions. Alternatively, dry ball milling is a scalable and economically viable technique for producing MoS2/Graphite heterostructures. The process uses mechanical forces exerted by balls to strip layered materials through their weaker van der Waal’s bonding. To date, the only MoS2/Graphite composite synthesised with this method (though under Ar) for Li-ion batteries, was ball milled for 40 hrs and exhibited a practical capacity of ~700 mA h g-1 at 100 mA g-1 current density for 100 cycles.(1) This work uses simple dry ball milling under atmospheric conditions for 12 hrs to synthesise a MoS2/Graphite composite which exhibits ~350 mA h g-1 at a high current density of 1 A g-1. Additionally, this work shows that dry ball milling MoS2 alone for 12 hrs produces a phase transformation to a conductive 1T MoS2 product. Raman spectroscopy, XRD, XPS, SEM and impedance spectroscopy techniques were used to characterise the materials. By combining MoS2 and graphite with this simple and scalable method, we provide a viable solution to meet rising consumer demands of improved energy storage devices. (1) Zhao H, Zeng H, Wu Y, Zhang S, Li B, Huang Y. Facile scalable synthesis and superior lithium storage performance of ball-milled MoS2-graphite nanocomposites. J Mater Chem A. 2015;3(19):10466–70.