We report the synthesis of heterodimensional nanostructures of MoS2 quantum dots interspersed in few-layered sheets of MoS2, using a liquid exfoliation technique in organic solvents. This unique hybrid morphology results from the optimized experimental conditions involving bath sonication followed by ultrasound probe sonication. We show that such heterodimensional hybrid materials could easily be extracted from the solvent as precipitates when post-treated with less polar volatile solvents such as chloroform. Such tailored MoS2 nanostructures, when directly used as electrodes for hydrogen evolution reaction, showed excellent electrocatalytic activity with low overpotential. Hence, we believe this could lead to large-scale synthesis of liquid-exfoliated layered nanostructures for their potential applications.

Organic materials for Li-ion battery application continue gaining attention due the virtue of low cost, environmental benignity, and so on. A new class of electroactive organic material called polyimides is particularly important due to the extra stability exhibited at higher current rates. High-performance rechargeable lithium battery cathodes based on polyimides of 3,4,9,10-perylenetetracarboxylicacid-dianhydride are prepared. The novel electrodes exhibit good rate capability and improved cycling stability, which result from their combined beneficial properties such as the presence of additional carbonyl groups, favorable band gap, and enhanced conductivity, making it a potential material for greener and sustainable electrochemical storage devices. SECTION: Energy Conversion and Storage; Energy and Charge Transport S torage and utilization of sustainable energy via an environmentally friendly route is an important aspect of energy economy. 1−3 With a growing need for clean and efficient energy-storage technologies, rechargeable Li-ion batteries are undoubtedly the state-of-the-art and hence continue to gain both scientific and commercial importance for their applications in portable electronics and vehicular sector. 4−6 However, designing advanced batteries that are highly energy efficient and eco-friendly is still a major challenge. The current Li-ion battery technology with active inorganic insertion electrode materials such as LiCoO 2 fails to fulfill the demand in terms of safety and sustainability. Recently, there has been wide interest toward developing "greener and sustainable" rechargeable lithium batteries based on organic electrode-active materials. 7−10 Research on organic electrodes for rechargeable lithium batteries, although started several years back, did not gain much importance until recently, partially due to their poor performances and wide acceptance of transitional-metal-based inorganic electrodes. Transition from inorganic to organic material-based electrodes could be a possible alternative, and several groups have turned toward "organic approach", thanks to the rich and versatile chemistry available for organic synthesis that allows the design of electrode materials with high level of control over the functionalities and tunable redox properties without the use of heavy metals and hightemperature synthesis. 1 In recent years, several redox-active organic materials such as organosulphur, 11 radical polymers, 12,13 and carbonyl 14 -based compounds have been studied as electrodes for Li-based batteries and were reported to exhibit reversible reactivity with Li. However, the performance characteristics of such organic electrodes for their application in Li-ion battery were limited due to several factors such as electrode dissolution, thermal instability, and so on. Reversible redox properties of carbonyl-based organic molecules have been extensively studied by several groups. 1,10,14−16 Nevertheless, organic-based materials present some drawbacks such as low thermal stability, low conductivit...

Size-controlled synthesis of luminescent quantum dots of MoS2 (≤2 layers) with narrow size distribution, ranging from 2.5 to 6 nm, from their bulk material using a unique electrochemical etching of bulk MoS2 is demonstrated. Excitation-dependent photoluminescence emission is observed in the MoS2 QDs. "As-synthesized" MoS2 QDs also exhibit excellent electrocatalytic activity towards hydrogen evolution reactions.

Organic rechargeable batteries gain huge scientific interest owing to the design flexibility and resource renewability of the active materials. However, the low reduction potentials still remain a challenge to compete with the inorganic cathodes. This study demonstrates a simple and efficient approach to tune the redox properties of perylene diimides (PDIs) as high voltage cathodes for organic‐based sodium‐ion batteries (SIBs). With appropriate electron‐withdrawing groups as substituents on perylene diimides, this study shows a remarkable tunability in the discharge potential from 2.1 to 2.6 V versus Na+/Na with a sodium intake of ≈1.6 ions per molecule. Further, this study explores tuning the shape of the voltage profiles by systematically tuning the dihedral angle in the perylene ring and demonstrates a single plateau discharge profile for tetrabromo‐substituted perylene diimide (dihedral angles θ1 & θ2 = 38°). Detailed structural analysis and electrochemical studies on substituted PDIs unveil the correlation between molecular structure and voltage profile. The results are promising and offer new avenues to tailor the redox properties of organic electrodes, a step closer toward the realization of greener and sustainable electrochemical storage devices.

Developing new approaches to improve the performance of organic electrodes for rechargeable sodium batteries is important. Here we report studies on N,Nʹ-diamino-3,4,9,10 perylenetetracarboxylic polyimide (PI) as a novel cathode for sodium battery and demonstrate an all-organic sodium ion battery using this polyimide as cathode and disodium terephthalate (NaTP) (pre-sodiated) as anode. The synthesised PI exhibits excellent electrochemical properties, when studied as cathode for sodium batteries, with a reversible capacity of 126 mAhg -1 along with good capacity retention and rate capability, in the voltage range of 1.5 to 3.5 V vs. Na + /Na. The all-organic sodium ion full cell delivered an initial capacity of 73 mAhg -1 , with an average cell voltage of 1.35 V. The attractive electrochemical performance combined with the design flexibility of PTCDA based PI material, offer new possibilities for the development of efficient all-organic sodium batteries.