Electrochemical studies of novel olivine-layered (LiFePO4-Li2MnO3) dual composite as an alternative cathode material for lithium-ion batteries

Journal of Solid State Electrochemistry - In the present work, olivine-layered composites, i.e., LiFePO4-Li2MnO3, are successfully synthesized in the form of a single monolithic electrode and layer...     

Catalyst‐free one‐pot regioselective synthesis of benzo[d]imidazo[2,1‐b]thiazoles by heating or grinding

Eco‐friendly, efficient, and simple one‐pot catalyst‐free new procedures have been reported for the synthesis of benzo[d]imidazo[2,1‐b]thiazoles by condensation of phenylglyoxal, cyclic enolizable carbonyl compounds, and 2‐aminobenzothiazole at 80°C or by grinding the components at room temperature in glycerol. Cyclic enolizable carbonyl compounds employed in the protocol include dimedone, cyclohexa‐1,3‐dione, cyclopenta‐1,3‐dione, 5‐methylcyclohexa‐1,3‐dione, and 4‐hydroxy‐6‐methyl‐2‐pyrone. All the reactions were complete in ~30 min. The structures of all the products were confirmed by spectral data. The structures of compounds IVl and IVe have also been confirmed by X‐ray crystallographic studies. This protocol offers advantages such as short reaction time, easy workup, high yields and an environmentally benign methodology.     

Synthesis and electrochemical characterization of graphene nanoflakes and LiFe<Subscript>0.97</Subscript>Ni<Subscript>0.03</Subscript>PO<Subscript>4</Subscript>/C for lithium-ion battery

The graphene nanoflakes and olivine-type LiFe_0.97Ni_0.03PO₄/C (LFNP3/C) samples have been synthesized as anode and cathode materials, respectively. Physicochemical characterization of the graphene nanoflakes and LFNP3/C material were studied using X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD patterns reveal the formation of the pure phase of both the synthesized samples. SEM micrographs disclose the formation of spherically shaped nanosized particles for LFNP3/C while graphene shows flake-type morphology. CR2032 half and full coin cells were assembled for electrochemical testing of the synthesized samples. Cyclic voltammetry (CV) results indicate that the graphene-based half-cells, i.e., GN1H and GN2H, possess reduction peak/plateau around 0.17 V while LFNP3/C cathode shows discharging voltage plateau at 3.4 V vs. Li/Li⁺. The discharge capacities were found to be 700, 900, and 153 mAhg^?1 for GN1H, GN2H, and LFNP3/C half-cells vs. Li/Li⁺, respectively. Among full cells, LFPGN1F with γ = 0.75 (mass/capacity balancing factor) shows better charging/discharging profile at each C-rate as compared to LFPGN2F with γ = 0.55. LFPGN1F delivered an initial discharge capacity of around 154 mAhg^?1 at 0.1C and even at a high discharge rate of 1C, it retained ~97% of the discharge capacity as compared to the initial cycle at the same rate.     

Nickel boride mediated chemoselective deprotection of 1,1-diacetates to aldehydes and deprotection with concomitant reduction to alcohols at ambient temperature

A variety of 1,1-diacetates have been chemoselectively and efficiently deprotected to the corresponding aldehydes as well as deprotected and concomitantly reduced to the corresponding alcohols in high yields at ambient temperature with nickel boride generated in situ using different molar ratios of sodium borohydride and nickel (II) chloride in methanol at room temperature. Deprotection and reduction of a variety of aromatic, aliphatic and heterocyclic acylals have been achieved efficiently. Mild reaction conditions, easy work-up, high yields and chemoselectivity demonstrate the efficiency of this new method.