As renewable energy is becoming a critical energy source to meet the global demand, electrochemical energy storage devices become indispensable for the efficient energy storage and reliable supply. The electrode material is the key factor determining the energy storage capacity and the power delivery of the devices. Carbon-based materials, specifically graphite, activated carbons etc., are extensively used as for electrodes, yet their low energy densities impede the development of advanced energy storage materials. Decoration by nanoparticles of metals, metal oxides, nitrides, carbides, phosphides, chalcogenides, and bimetallic components is one of the most promising and easy-to-implement strategies to significantly enhance the structural and electronic properties, pore refinement, charge-storage, and charge-transfer kinetics of both pristine and doped carbon structures, thereby making their performance promising for next-generation energy storage devices. Structuring the materials at nanoscale is another probable route for better rate performance and charge-transfer kinetics. This review covers the state-of-art nanoparticle decorated nanocarbons as materials for battery anode, metal-ion capacitor anode, and supercapacitor electrode. A critical analysis of the elemental composition, structure, associated physico-chemical properties and performance relationships of nanoparticle-decorated nanocarbon electrodes is provided as well to inform the future development of the next generation of advanced energy storage materials and devices.

In the science and technology of electrochemical energy storage, different allotropes of MnO2, fabricated with a variety of methods, are assembled into electrodes, playing the role of cathode or oxygen reduction reaction (ORR) electrocatalyst. Often, MnO2‐based cathodes are combined with Zn anodes into different types of batteries, resulting in contact between MnO2 and its electrochemical reaction products, and Zn2+. Awareness is growing that this interaction adversely affects the functional performance of MnO2, but no definitive understanding has been reached for this issue. This study contributes, through electrochemical measurements accompanied by microscopy and Raman spectroscopy, to a better understanding of the way the electrochemical behavior of two technologically representative types of manganese dioxide ‐ hydrothermally grown α‐MnO2 and electrodeposited γ‐MnO2 (EDM) ‐ is degraded when these materials are exposed to neutral and alkaline aqueous solutions, containing Zn2+. Specifically, we highlighted different types of irreversible changes in electrochemical response, which can be interpreted with phase‐formation processes. Such changes result in the deactivation of α‐MnO2 as ORR electrocatalyst, and of both α‐MnO2 and EDM as zinc‐ion battery (ZIB) cathodes. The electroactivity of EDM for ZIB operation can be restored if Mn2+ is added to the neutral electrolyte, because a phase, active in discharge, is electrodeposited during charging.

Among post-lithium ion battery technologies, rechargeable chemistries with Zn anodes bear notable technological promise owing to their high theoretical energy density, lower manufacturing cost, availability of raw materials and inherent safety. However, Zn anodes, when employed in aqueous electrolytes, suffer from hydrogen evolution, passivation, and shape changes. Alternative electrolytes can help tackle these issues, preserving the green and safe characteristics of aqueous-based ones. Deep eutectic solvents (DESs) are promising green and low-cost non-aqueous solvents for battery electrolytes. Specifically, the cycling of Zn anodes in DESs is expected to be reversible, chiefly owing to their dendrite-suppression capability. Nevertheless, apart from a few studies on Zn plating, insight into the cathodic–anodic electrochemistry of Zn in DESs is still very limited. In view of developing DES-based battery electrolytes, it is crucial to consider that a potential drawback might be their low ionic conductivity. Water molecules can be added to the eutectic mixtures by up to 40% to increase the diffusion coefficient of the electroactive species and lower the electrolyte viscosity without destroying the eutectic nature. In this study, we address the electrochemistry of Zn in two different hydrated DESs (ChU and ChEG with ~30% H2O). Fundamental electrokinetic and electrocrystallization studies based on cyclic voltammetry and chronoamperometry at different cathodic substrates are completed with a galvanostatic cycling test of Zn|Zn symmetric CR2032 coin cells, SEM imaging of electrodes and in situ SERS spectroscopy. This investigation concludes with the proposal of a specific DES/H2O/ZnSO4-based electrolyte that exhibits optimal functional performance, rationalized on the basis of fundamental electrochemical data, morphology evaluation and modeling of the cycling response.

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The applications of SERS in therapeutic drug monitoring, or other fields of analytical chemistry, require the availability of sensitive sensors and experimental approaches that can be implemented in affordable ways. In this contribution, we show the production of cost-effective SERS sensors obtained by depositing Lee-Meisel Ag colloids on filter paper either by natural sedimentation or centrifugation. We have characterized the morphological and plasmonic features of the sensors by optical microscopy, SEM, and UV-Vis spectroscopy. Such sensors can be used to quantify by SERS the anti-epileptic drug Perampanel (in the concentration range 1 × 10−4–5 × 10−6 M) by spinning them during the micro-Raman measurements on the top of a custom device obtained from spare part hard disk drives. This approach minimizes laser-induced heating effects and allows averaging over the spatial non-uniformity of the sensor.