Polyanionic-type electrode material made of (PO4) n− polyhedral covalently bonded with Ni–O linkage is envisaged as a novel electrode material for intercalative battery-type hybrid supercapacitors. Highly porous, flake-type KNiPO4 showed robust electrochemical performances as a result of its open framework structure and active participation of the Ni2+/3+ redox couple that results in superior pseudocapacitive intercalating charge storage in the aqueous KOH electrolyte. The KNiPO4 electrode shows the specific charge storage equivalent to 168.5 mAh/g (capacitance of 935 F/g) at 1 A/g current rate in the potential window of 0.65 V in the aqueous 2 M KOH electrolyte. KNiPO4 electrodes exhibit excellent long-term cycle stability at 10 A/g for 5000 cycles with 87% of the initial capacity retention of the electrode and coulombic efficiency (η = t d/t c) equivalent to 95.1% after 5000 cycles. Further, in full cell hybrid supercapacitor (HSC) mode in which porous KNiPO4 acted as the positive electrode and activated carbon (AC) functioned as the negative electrode, in the voltage window of 1.6 V, the highest energy density equivalent to 200 Wh/kg and power density equivalent to ∼819 W/kg were obtained at 1 A/g current rate. At a higher current rate (10 A/g), the hybrid supercapacitor attains a very high power density equivalent to 7981 W/kg with a retention of energy density close to 75 Wh/kg with superior cyclic stability. Coulombic efficiency of the full cell [asymmetric supercapacitor (ASC) mode] has lost only 3.4% with excellent capacity retention (92.3%) of its initial value after 2200 cycles. The robust performance and long cycle life of the electrode in full cells confirm the applicability of the material to power implantable biomedical devices. Further, high power performance coupled with superior cyclic stability coupled with strong electrochemical energy storage properties of the KNiPO4 electrode makes it suitable for bulk, grid-level charge storage applications.

Field experiments showed t h a t soil compaction did not affect wheat yield significantly under rainfed conditions. Weed population was significantly reduced due to soil compaction. Compaction decreased total moisture use and increased water use efficiency. There was better and profitable utilization of stored soil moisture from the compaction t r e a t m e n t s as compared to no compaction treatment.Placement of nitrogen about 10 to 15 cm deep in the soil directly below the seed resulted in significant increase in the yield of wheat crop grown under rainfed conditions. Weed population was not affected due to nitrogen placement. Total moisture use reduced due to nitrogen placement. U n d e r rainfed conditions, deep placement of nitrogen was i m p o r t a n t for increasing the efficiency of fertilizer as well as water utilization by wheat crop.

The as-prepared La1-xKxCoO3- (0≤x≤0.5) showed superior pseudocapacitive charge storage capacity in neutral 0.5M Na2SO4 electrolyte and superior electrocatalytic activities for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR)...

Due to the limiting lithium reserve and increasing price of lithium, alternatives to Li-ion batteries are growing rapidly. The world is now focusing on developing electrodes beyond Li-ion-based rechargeable batteries for portable electronics. Iron, nickel, and Co-based NASICON structured materials give stable capacity with reversible intercalation of almost one sodium in the host lattice. In the current work, we suggest a cathode material made of 3D framework-structured molybdenum polyanionic phosphate (Mo2P2O11) for a reversible sodium-ion battery. Mo2P2O11 was synthesized using the heat treatment of the MoO2HPO4·H2O precursor at 560 °C, having the morphology of stacked flakes. Characterization techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray were utilized for confirming the structure and morphology of the materials. For electrochemical performance, cyclic voltammetry, charge–discharge, and stability tests have been performed. Mo2P2O11 work through the active participation of the Mo6+/4+ redox couple with reversible intercalation of Na+ ions. The electrode exhibits reversible intercalation at 3.0 V versus Na and a steady capacity of ∼90 mA h/g, that is, ∼1.4 Na per formula unit, achieving a Coulombic efficiency of nearly 100%. The current finding opens up a new route for using transition-metal phosphates as efficient and stable charge storage cathode materials for sodium-ion batteries.

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