Facile synthesis of high electrical conductive CoP via solid-state synthetic routes for supercapacitors

Co-P precursor was prepared by a mechanical alloying method and then is controlled to synthesis of CoP phase through an annealing method. The optimal conditions of ball milling and annealing temperature are investigated. The CoP exhibits higher electrical conductivity than graphite and cobalt oxide, showing excellent pseudocapacitive properties due its high electrical conductivity which can result in a fast electron transfer in high rate charge-discharge possess. The as-obtained CoP electrode achieves a high specific capacitance of 447.5 Fig at 1 Aug, and displays an excellent rate capability as well as good cycling stability. Besides, the asymmetric supercapacitor (ASC) based on the CoP as the positive electrode and activated carbon (AC) as the negative electrode was assembled and displayed a high rate capability (60% of the capacitance is retained when the current density increased from 1 Aug to 12 Aug), excellent cycling stability (96.7% of the initial capacitance is retained after 5000 cycles), and a superior specific energy of 19 Wh/kg at a power density of 350.8 W/kg. The results, suggest that the CoP electrode materials have a great potential for developing high-performance electrochemical energy storage devices. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

New Type of Nitrides with High Electrical and Thermal Conductivities

The nitrogen dimer as both a fundamental building unit in designing a new type of nitrides, and a material gene associated with high electrical and thermal conductivities is investigated by first principles calculations.The results indicate that the predicted Si N4 is structurally stable and reasonably energy-favored with a striking feature in its band structure that exhibits free electron-like energy dispersions. It possesses a high electrical conductivity（5.07 × 10^5 S/cm） and a high thermal conductivity（371 W/m·K） comparable to copper. The validity is tested by isostructural Al N4 and Si C4. It is demonstrated that the nitrogen dimers can supply a high density of delocalized electrons in this new type of nitrides.

Constructing Carbon Nanobubbles with Boron Doping as Advanced Anode for Realizing Unprecedently Ultrafast Potassium Ion Storage

Carbonaceous material with favorable K^(+)intercalation feature is considered as a compelling anode for potassium-ion batteries(PIBs).However,the inferior rate performance and cycling stability impede their large-scale application.Here,a facile template method is utilized to synthesize boron doping carbon nanobubbles(BCNBs).The incorporation of boron into the carbon structure introduces abundant defective sites and improves conductivity,facilitating both the intercalation-controlled and capacitivecontrolled capacities.Moreover,theoretical calculation proves that boron doping can effectively improve the conductivity and facilitate electrochemical reversibility in PIBs.Correspondingly,the designed BCNBs anode delivers a high specific capacity(464 mAh g^(-1)at 0.05 A g^(-1))with an extraordinary rate performance(85.7 mAh g^(-1)at 50 A g^(-1)),and retains a considerable capacity retention(95.2%relative to the 100th charge after 2000 cycles).Besides,the strategy of pre-forming stable artificial inorganic solid electrolyte interface effectively realizes high initial coulombic efficiency of 79.0%for BCNBs.Impressively,a dual-carbon potassium-ion capacitor coupling BCNBs anode displays a high energy density(177.8 Wh kg^(-1)).This work not only shows great potential for utilizing heteroatom-doping strategy to boost the potassium ion storage but also paves the way for designing high-energy/power storage devices.

A novel Sn-based coordination polymer with high-efficiency and ultrafast lithium storage

Recently,Coordination Polymers(CPs)have been widely utilized as energy storage materials for reversible Lithium-Ion Batteries(LIBs)benefiting from their tunable building blocks and adjusted electrochemical properties.However,the unsatisfied electrochemical behavior of CPs with poor conductivity and sluggish ion transport kinetics is still a bottle-neck for their large-scale energy storage applications in LIBs.Herein,we display the rational fabrication of a conductive Sn-based coordination polymer(Sn-DHTPA)via judiciously choosing suitable building units.The Sn-DHTPA is employed as anode for LIBs,exhibiting superior reversible storage capacity of 1142.6 m A h g^(-1) at 0.1 A g^(-1) after 100 cycles and impressive rate storage capability of 287.7 m A h g^(-1)at 20 A g^(-1).More importantly,a robust cycling performance of 205.5 m A h g^(-1) at an extra-high current density of 20 A g^(-1) are observed without remarkable capacity-fading up to1000 cycles.The behavior superiority of Sn-DHTPA is related to its advanced architecture with abundant lithium storage sites,high electrical conductivity and rapid lithium transport.A series of ex-situ characterizations reveal that the impressive lithium storage capacity is contributed by the redox active sites of both the aromatic linker and metal center related to in-situ generated metallic nanoparticles dispersed in the skeleton.