Hierarchical one-dimensional ammonium nickel phosphate microrods for high-performance pseudocapacitors

High-performance electrochemical capacitors will drive the next-generation portable, flexible and wearable electronics. Unlike the conventional all-carbon supercapacitors (electric double layer capacitors, EDLC) with high power but poor energy density, pseudocapacitors capitalize the high energy density inherent to reversible redox reactions and provide a facile means to enhancing the energy ratings of supercapacitors. The high length-to-diameter ratio and anisotropic character of 1-D architecture makes them suitable for use in energy storage. For the first time, we report 1-D microrod structures (∼ 36 nm width) of ammonium nickel phosphate hydrate (ANP mr) as a pseudocapacitor with high energy rating and power handling. To confirm the data, the ANP mr -based pseudocapacitor was subjected to various configurations (i.e., half-cell, symmetric, asymmetric, and flexible all-solid-state) and in each case it gave excellent values compared to any accessible literature to date. We clearly demonstrate that a flexible all-solid-state ANP mr -based pseudocapacitor achieved high areal capacitance of 66 mF cm ∼'2 with extra-ordinary energy (21.2 mWh cm ∼'2) and power (12.7 mW cm ∼'2) densities. This work opens doors for a facile, robust and scalable preparation strategy for low-cost, earth-abundant electrode materials for high-performance pseudocapacitors.CSIR (South Africa), the South Africa’s Department of Science and Technology (DST) and National Research Foundation (NRF) under the “Nanotechnology Flagship Programme” (supercapacitors and fuel cell project, Grant no. 69849)SP2016http://www.nature.com/articles/srep1762

Insights into the synergistic roles of microwave and fluorination treatments towards enhancing the cycling stability of P2-type Na0.67[Mg0.28Mn0.72]O2 cathode material for sodium-ion batteries

10.1149/2.1721713jesJournal of the Electrochemical Society16413A3362-A337

Effect of preparation temperature and cycling voltage range on molten salt method prepared SnO2

10.1016/j.electacta.2013.05.073Electrochimica Acta106143-148ELCA

Synthesis and Lithium Storage Properties of Zn, Co and Mg doped SnO2 Nano Materials

In this paper, we show that magnesium and cobalt doped SnO2 (Mg-SnO2 and Co-SnO2) nanostructures have profound influence on the discharge capacity and coulombic efficiency of lithium ion batteries (LIBs) employing pure SnO2 and zinc doped SnO2 (Zn-SnO2) as benchmark materials. The materials were synthesized via sol-gel technique. The structural, chemical and morphological characterization indicates that the Zn, Mg and Co dopants were effectively implanted into the SnO2 lattice and that Co doping significantly reduced the grain growth. The electrochemical performances of the nanoparticles were investigated using galvanostatic cycling, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The Co-SnO2 electrode delivered a reversible capacity of around 575 mAh g−1 at the 50th cycle with capacity retention of ∼83% at 60 mA g−1current rate. A capacity of ∼415 mAh g−1 when cycling at 103 mA g−1and >60% improvement in coulombic efficiency compared to the pure compound clearly demonstrate the superiority of Co-SnO2 electrodes. The improved electrochemical properties are attributed to the reduction in particle size of the material up to a few nanometers, which efficiently reduced the distance of lithium diffusion pathway and reduction in the volume change by alleviating the structural strain caused during the Li+ intake/outtake process. The EIS analyses of the electrodes corroborated the difference in electrochemical performances of the electrodes: the Co-SnO2 electrode showed the lowest resistance at different voltages during cycling among other electrodes