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Aqueous zinc-ion batteries (AZIBs) are an emerging sustainable and safer technology for large-scale electrical energy storage. Here, we report the synthesis of hybrid materials consisting of V2O5 nanoribbons (NRs) and reduced graphene oxide (rGO) nanosheets as AZIB cathode materials by divalent metal cation-mediated coprecipitation. The divalent metal ions M2+ (Zn2+ and Mn2+) effectively neutralize the negative charges on the surface of microwave-exfoliated crystalline V2O5 NRs and graphene oxide (GO) nanosheets to form a strongly bound assembly. After thermal annealing in a nitrogen atmosphere, GO is converted into rGO with higher electrical conductivity while the layers in V2O5 NRs are expanded by M2+ intercalation. When only Zn2+ ions are used during coprecipitation, the produced Zn-V2O5 NR/rGO hybrid shows a very high reversible specific capacity of ∼395 mAh g–1 at 0.50 A g–1 but suffers from poor stability. This is improved by mixing Mn2+ with Zn2+ ions during coprecipitation. The (Mn + Zn)-V2O5 NR/rGO hybrid shows a slightly lower specific capacity of ∼291 mAh g–1 at 0.5 A g–1 but a substantially improved long-cycling stability and better rate performance due to the stronger binding of Mn atoms in the V2O5 host that serve as stable pillars to support the expanded V2O5 layers.

This study reports the preparation of a set of hybrid materials consisting of Molybdenum disulfide (MoS2) nanopatches on reduced graphene oxide (rGO) nanosheets by applying the microwave specific heating of...

Highly conducting freestanding graphene (FSG) was synthesized by the simple vacuum filtration method and utilized as a cathode current collector for (fluorine doped tin oxide) FTO free quasi‐dye sensitized solar cell (q‐DSSC). Subsequently,conducting polymers (CPs) viz., polyaniline (PANI) and poly(3,4‐ethylene‐di‐oxythiophene) (PEDOT) was decorated on FSG surface by electrochemical polymerization which acts as a electrocatalytst for Pt free q‐DSSC. Entirely, the FSG/CPs affords as a novel cathode architecture for FTO/Pt free electrode for q‐DSSCs. Remarkably, the FSG paper electrode exhibits lower sheet resistance (9‐11 Ω sq‐1) than the FTO which was directly utilized as current collector. Interestingly, the FSG/CPs based cathode shows an improved electro‐catalytic behaviour towards tri‐iodide reduction and in particularly, the photovoltaic performance of FSG/PEDOT shows power conversion efficiency (PCE) of 5.4 % compared with Pt/FTO of 5.1 %. It can be stated that synergetic effect of FSG/PEDOT proves to be a cost effective and efficientsubstitute for cathodes in q‐DSSC.

Nowadays Solar energy is an important energy source due to the energy crisis and environment pollution. Maximum power point tracking (MPPT) algorithm improves the utilization efficiency of a photovoltaic systems. In this paper an improved P&O MPPT algorithm is developed and simulated using MATLAB / SIMULINK to control the DC/DC buck converter. The obtained simulink model is also verified using dspace tool. Both the simulated and experimental results are validated by also comparing them with conventional MPPT methods. The performance measures show the increase in the efficiency of PV system by the proposed model.

A Radial Basis Function based learning system method has been proposed for estimation of State of Charge (SOC) of lead Acid battery. Coulomb metric method is used for SOC estimation with correction factor computed by Radial Basis Function method. Radial Basis function based technique is used for learning battery performance variation with time and other parameters. Experimental results are included.

Rechargeable aqueous zinc ion batteries (AZIB) are an emerging topic in the battery research due to the high volumetric capacity of the zinc anode (5855 mAh/cm3), low cost, environmental friendliness and safety. But the development of the zinc ion batteries has been hindered by the slow insertion/extraction kinetics of the multivalent Zn2+ ions in the host structure mainly due to the larger ionic radii of the hydrated zinc ion (~4.60 Å) and stronger electrostatic interaction of the divalent metal cation with the host structure that monovalent Li+ ions. These factors make the existing Li-ion battery (LIB) cathode materials unfit for the intercalation/deintercalation of Zn2+ ion. Transition metal dichalcogenides like Molybdenum disulfide (MoS2) have caught the attention as a host for both monovalent and divalent ion storage due to their two-dimensional layered structure and high theoretical specific capacity for Li-ion storage (670 mAh g-1). The MoS2 structure consists of a two-dimensional (2D) layered structure with a layer of molybdenum atoms covalently bonded between two layers of sulfur atoms. The triatomic layers of MoS2 are linked by weak van der Waals forces similar to graphene, which can effectively accommodate the volume expansion to facilitate reversible intercalation/deintercalation of metal ions. Despite the advantages, MoS2 suffers from low electrical conductivity and pulverization of the structure after few intercalation/deintercalation cycles which causes rapid capacity fading. These problems can be mitigated by modifying the structure through (1) increasing the interlayer spacing (2) introducing active defects in the MoS2 structure to enhance Zn2+ ion adsorption, and (3) forming a hybrid structure with carbonaceous materials to improve the electrical conductivity, mechanical strength, and structural stability of MoS2 layers. Among which, defect engineering has been recently explored as an effective approach to enhancing the specific capacity of MoS2 towards the storage of monovalent and divalent ions including Li+, Na+, Zn2+ ions.In this work, the preparation of a set of hybrid materials consisting of Molybdenum disulfide (MoS2) nanopatches on reduced graphene oxide (rGO) nanosheets with controllable defect density and its impact on the storage of Li+ and Zn2+ ions will be presented and discussed. The MoS2/rGO hybrid materials are synthesized by applying the novel microwave specific heating of graphene oxide and molecular molybdenum precursors followed by a thermal annealing in 3% H2 and 97% Ar. The microwave process converts graphene oxide to ordered rGO nanosheets that are sandwiched between uniform thin layers of amorphous Molybdenum trisulfide (MoS3). The subsequent thermal annealing converts the intermediate layers into MoS2 nanopatches with 2D layered structures whose defect density is tunable by controlling the annealing temperature at 250°C (MoS2/rGO-250), 325°C (MoS2/rGO-325) and 600°C (MoS2/rGO-600), respectively. The defect-free MoS2/rGO-600 material performs well as an anode for Li+ io...

The available nutrient status of the mulberry gardens in the districts of Tamil Nadu is analyzed and evaluated to find the status. In this work, the soil is classified based on the test report to a number of features with fertility indices for boron (B), organic carbon (OC), potassium (K), phosphorus (P), and available boron (B), along with the parameter soil reaction (pH). A total of 10 steps are used for cross-validation purposes wherein in every step, the data involves 10% for validation and the remaining for training data. A fast learning classification methodology known as extreme learning method (ELM) is trained using the data to identify the micronutrients present in the soil. Activation functions such as hard limit, triangular basis, hyperbolic tangent, sine-squared, and Gaussian radial basis are used to optimize the methodology. Based on the analysis performed, the nutrients are classified and the optimal soil conditions are proposed for different regions that are analyzed. Based on the study conducted, it is found that the soils in Tamil Nadu have normal electrical conductivity and are red in colour. They are found to be rich in potassium (35% of the samples), nitrogen (80% of the samples), and sulphur (75% of the sample) and sufficient or poor in magnesium, boron, zinc, and copper.