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A novel finding that the electrochemical performance of the commercial lithium titanate (Li4Ti5O12, LTO) can be significantly improved by using a novel current collector of CuI particles modified copper foil is reported for the first time in this work. Firstly, a large number of particles with well-defined shapes were prepared on the commercial copper foil surface via a very simple soaking process, in which the soaking solution contained only CuSO4, H2SO4 and [Bmim]I. As indicated by the XRD and XPS measurements, the particles observed on the surface of the copper foil were identified as CuI particles. That is, CuI particles modified copper foils (denoted as CuI/Cu) were successfully prepared at room temperature. CuI/Cu prepared in the presence of 0.4, 0.6 and 0.8 g of [Bmim]I were nominated as CF (copper foil) a, b and c, respectively. Inconceivably, as compared to the conventional LTO electrode, the LTO electrodes assembled using the newly prepared CFs exhibited a significantly improved electrochemical performance, i.e., all as-prepared CFs showed an evident promoting effect on the electrochemical performance of the traditional LTO electrodes. For instance, the initial discharge capacity (DC) of the LTO electrode assembled using CF b (called electrode b) at 0.2 C was 307 mAh g−1, which was about 1.86 times higher than that of the LTO electrode prepared using the conventional copper foil current collector (165 mAh g−1). Particularly, as the applied current rate was as high as 10 C, the DC value of electrode b (117 mAh g−1), even after 100 cycles, was still about 2.54 times that of the traditional LTO electrode (46 mAh g−1). In this preliminary work, a new method for preparing CuI particles was developed, along with a novel approach to significantly improve the electrochemical properties of the commercial LTO electrode. The method did not require any strong oxidants or reducing agents, nor did it demand any additional energy expenditure during the preparation of CuI particles. Moreover, the approach did not require any changes in the assembly procedure for the LTO electrodes being studied. This work was very meaningful for the development of the CuI-related research field as well as for the electrochemical performance improvement of LTO-based lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

For the first time, peony-shaped micron-sized nickel oxide (NiO) particles are fabricated through a hydrothermal process–assisted air calcination method using nickel acetate tetrahydrate (NAT) and the spent bicycle tires–derived porous carbon particles as the starting materials. Firstly, porous carbon particles (PCPs) are prepared via an air calcination-acid pickling-air drying method using the spent bicycle tires as the raw materials. Then, the products prepared using PCPs and NAT with a mass ratio of 3:10, 3:20, and 3:30 are, respectively, nominated as sample a, b, and c. XRD and XPS analyses reveal that, besides the amorphous carbon materials, NiO as the main product exists in all prepared samples. Interestingly, as exhibited by the SEM images, a large piece of luxuriant flower assembled by many smaller and broken petals, well-defined peony-shaped micron-sized particles, and a large piece of luxuriant flower wove by a large number of larger petals are displayed clearly in sample a, b, and c, respectively. When being used as electrode materials of LIBs, the initial discharge capacity (DC) value at 100 mA g−1 delivered by sample b is as high as 1013 mAh g−1 and, even after 20 cycles, the DC value is still maintained to be 518 mAh g−1. Most importantly, the DC value of sample b at 1 A g−1 after 50 cycles is still kept to be 138.7 mAh g−1, almost 2.8 times larger than that of the commercial graphite (50.1 mAh g−1), presenting an excellent high rate performance. This work is very favorable not only to the development of NiO-based LIBs anode materials due to the superior electrochemical performance, but also to the further exploration of NiO related research fields owing to the special peony-shaped morphology. [ABSTRACT FROM AUTHOR]

In the present study, we have proposed the phosphorus (P)-doped CoS2 electrocatalyst through a simple hydrothermal route and utilized as an economical and earth-abundant electrocatalyst for hydrogen evolution reaction (HER). A sequence of P-doped CoS2 electrocatalysts were obatined by using different NaH2PO4 contents. The as-synthesized samples were characterized by XRD, SEM, HR-TEM, element mapping, and XPS analyses. It is found that these P-doped CoS2 materials composed of high purity nanoparticles and stacked in a block structure. The electrochemical performance has been investigated in 0.5-M H2SO4 electrolyte. The results indicate that the doping of phosphorus can significantly increase the electrocatalytic hydrogen evolution activity of CoS2. Among the different samples, the P-doped CoS2 attained with 5 mmol of NaH2PO4 contents offers the highest HER performance with a minimum overpotential of 109 mV at 10 mA cm-2, the smallest Tafel slope of 48 mV dec-1, and an excellent long-term durability over 1,000 cycles. The analysis results illustrate that the doped phosphorus may change the internal properties of CoS2, which promotes the ability of charge transfer and electrochemical active sites, resulting in the significantly increased HER activity compared with bare CoS2. Therefore, this work demonstrates that a proper doping of phosphorus is a suitable approach to improve the catalytic ability of metal sulfides for HER application. [ABSTRACT FROM AUTHOR]

Herein, we reported a novel carbon nanotubes@porous carbon/sulfur (CNT@PC/S) composite with huge specific capacity for rechargeable lithium-sulfur battery. The porous carbon has a large surface area and appropriate pore size which derived from the aluminum-based metal-organic framework (Al-MOF). The obtained electrochemical results show the CNT@PC/S composite with 50% of sulfur content displays superior discharge specific capacity of 424 mAh g−1 after 100 cycles at a rate of 0.5 C with a better coulombic efficiency of 98%. Furthermore, the optimized CNT@PC/S composite offered a large discharge specific capacity of 271.2 mAh g−1 using ultra-fast rate of 2 C. The pore structure of CNT@PC encapsulates with the elemental sulfur, which is efficiently inhibiting the diffusion of polysulfide ions in electrolyte, resulting in the greatly improve the ability of volume changes during the charge-discharge process. Therefore, the as-prepared CNT@PC/S composite can be a talented cathode material for lithium-sulfur battery and other electrochemical devices. [ABSTRACT FROM AUTHOR]

In this study, we synthesized nitrogen-doped Mo2C@carbon nanotube (N-Mo2C@CNT) composites via a facile one-pot method of solvothermal followed by calcination. The SEM and TEM results of N-Mo2C@CNT composites show that the sphere-shaped N-Mo2C is covered by CNTs. In addition, the electrocatalytic performances of the as-obtained N-Mo2C@CNT composites were examined towards the hydrogen evolution reaction (HER) in acidic media. It is revealed that the N-Mo2C@CNT composite with optimum content of CNTs (30 mg) exhibits an excellent catalytic activity with less overpotential of 183 mV at 10 mA cm−2 and smaller Tafel slope of 73.95 mV dec−1 as compared with pure Mo2C. Furthermore, it has a good cycling stability after 1000 cycles. This enhanced activity due to the creation of more active sites, large specific surface area by better synergistic effect between the N-Mo2C and CNT. Consequently, the N-Mo2C@CNT composite is a viable alternative to the noble metal electrocatalysts for HER. [ABSTRACT FROM AUTHOR]

Nano-Ag4Bi2O5/MnOx@rGO ternary composite was prepared via a facile coprecipitation method in rGO dispersed concentrated KOH solution under precisely controlled conditions. Morphology characterizations indicate that the Ag4Bi2O5/MnOx composite with corncob-like shape of 200 nm in length and 50 nm in width is loaded on the wrinkled rGO. The electrochemical tests find that the optimized ternary catalyst with 60% rGO contained offers much higher initial potential (0.0799 V vs. Hg/HgO) and limiting current density (6.164 mA cm−2) than that of the standardized Pt/C (0.017 V and 5.09 mA cm−2) at a rotation rate of 1600 rpm. Furthermore, the catalyst possesses preferable durability and anti-methanol as compared with Pt/C. The Ag4Bi2O5/MnOx/rGO with surperior ORR properties indicates that it will be a promising catalyst for oxygen reduction reaction in alkaline electrolyte. [ABSTRACT FROM AUTHOR]

This paper reports a novel green and energy-saving method to prepare ultrahigh-purity lead from spent lead plate grids via a pressing-electrorefining process. The lead plate grids from spent lead-acid batteries were firstly pressed into high-density crude lead plates, then the crude lead plates were electro-refined in a NaOH–NaHPbO2 solution plus additive of JZ04 to recover an ultrahigh-purity lead. This paper systematically studied the effects of electrolyte temperature, the concentration of NaOH and Pb2+, additives, and current density on the anodic stripping process, cathodic electrodeposition process, and electrorefining process via constant current electrolysis, AC impedance, and LSV methods. The lead plate grids, anodic stripping product, and cathodic electrodeposited lead were examined by field emission scanning electron microscope, EDS, XPS, and ICP analytical methods. Results show that under the optimum conditions, the energy consumption of electrodeposition is only 18 kW·h·(t Pb)−1 with the recovery efficiency of 99.7%; the purity of obtained lead reaches 99.9991%, much higher than the criteria of the European (EN 12659-1999, 99.99%) and the Chinese standard (GB/T 469-2013, 99.994%). [ABSTRACT FROM AUTHOR]

Nitrogen-doped hierarchical porous carbon is successfully synthesized from cauliflower with unique structure by a simple pyrolysis process, including a pre-carbonization step of cauliflower and a KOH-activated step of carbonization product. According to this pyrolysis strategy, the pre-carbonization product at 450 °C basically keeps the original structure of cauliflower, beneficial to the deep and uniform activation at 700 °C and the formation of 3D interconnected network framework. The as-prepared sample (NPCC2-700) shows desirable specific surface area of 2604.7 m2 g−1, large pore volume, and abundant micropores and mesopores. Combined with the high content of active heteroatoms, NPCC2-700 exhibits high specific capacitance of 311 F g−1 at 1 A g−1 and 250 F g−1 at 50 A g−1 in 6M KOH electrolyte. Meanwhile, the excellent rate performance and long-term cycling stability can be achieved for NPCC2-700. Furthermore, the energy density of the assembled symmetric supercapacitor based on NPCC2-700 electrodes is as high as 20.5 Wh kg−1 at a power density of 448.8 W kg−1 in 1 M Na2SO4 solution. [ABSTRACT FROM AUTHOR]

In this paper, we propose a full lead single flow battery with ultra-high specific surface capacity, which is achieved by the combined effects of electrochemically deposited lead as a negative electrode, electrodeposited PbO on Pt-plated titanium (Pt/Ti) plate as a positive electrode, and the composite perchloric acid with additives as an electrolyte. Experimental results indicate that this newly developed single flow battery provides a specific surface capacity of 125 mAh cm, five times higher than that of the traditional lead single flow batteries using methanesulfonic acid or fluoroboric acid. The new lead single flow battery shows a good cycling performance with an average capacity efficiency of 95% and an energy efficiency of 85% after 500 cycles. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) structured electrode in which a compact CeO-β-PbO particle layer on each carbon fiber in the felt (denoted as CF/CeO-β-PbO) was fabricated using cyclic voltammetry (CV) method in the presence of CeO nanoparticles in the electrolyte and supposed to be used as a sensor for in situ chemical oxygen demand (COD) detection. It was found that CeO was codeposited with PbO onto the anode, and the deposited crystals were tiny and compacted with each other. The electrochemical behaviors demonstrate that the fabricated CF/CeO-β-PbO electrode possesses larger effective surface area, higher electrochemically catalytic activity, and better mechanical stability as compared with the anode without CeO deposited by CV method or constant potential (CP) method. The results of COD determination by the fabricated CF/CeO-β-PbO electrode show a sensitivity of (3.0 ± 0.02) × 10 mA cm/mg L, a detection limit of 3.6 mg L ( S/ N = 3) and a linear range of 30-8500 mg L with correlation coefficient ( R) of 0.9985 and RSD within 5 %. [ABSTRACT FROM AUTHOR]

Accompanying the rapid growth of China's population and economy, energy consumption and carbon emission increased significantly from 1978 to 2012. China is now the largest energy consumer and CO emitter of the world, leading to much interest in researches on the nexus between energy consumption, carbon emissions and low-carbon economy. This article presents the domestic Chinese studies on this hotpot issue, and we obtain the following findings. First, most research fields involve geography, ecology and resource economics, and research contents contained some analysis of current situation, factors decomposition, predictive analysis and the introduction of methods and models. Second, there exists an inverted 'U-shaped' curve connection between carbon emission, energy consumption and economic development. Energy consumption in China will be in a low-speed growth after 2035 and it is expected to peak between 6.19-12.13 billion TCE in 2050. China's carbon emissions are expected to peak in 2035, or during 2020 to 2045, and the optimal range of carbon emissions is between 2.4-3.3 PgC/year (1 PgC=1 billion tons C) in 2050. Third, future research should be focused on global carbon trading, regional carbon flows, reforming the current energy structure, reducing energy consumption and innovating the low-carbon economic theory, as well as establishing a comprehensive theoretical system of energy consumption, carbon emissions and low-carbon economy. [ABSTRACT FROM AUTHOR]

To pursue high performance for nonenzymatic glucose sensor, fast conversion of redox couple (Ni(OH)↔NiOOH: Ni/Ni) was established on Ni(OH) nanoparticles modified carbon (Ni(OH)/C) composite electrode coupling with concentrated hydroxide electrolyte. The electrode was prepared by in situ precipitation of nano-Ni(OH) on carbon and then treated by cyclic voltammetry. Cyclic voltammetry was also used to identify the extremely high conversion rate of Ni/Ni on the prepared composite electrode. Continuous cyclic voltammetry method with increasing the concentration of glucose on each cycle step by step was employed to promptly determine linear range and appropriate potential for glucose detection in 0.1, 1, and 7 M KOH electrolyte. The amperometric measurement under the optimized condition (0.28 V vs. saturated calomel electrode (SCE) in 7 M KOH) showed that the Ni(OH)/C composite electrode exhibits a sensitivity of 1004.6 μA mM cm in a wide linear range from 1 μM to 15 mM ( R = 0.9999). What is more, favorable selectivity, reproducibility, and stability for glucose detection were also obtained. These performances indicated that the proposed Ni(OH)/C nanocomposite sensor with fast conversion of redox couple is a promising nonenzymatic glucose sensor. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In multiuser multiple-input single-output (MISO) systems, non-linear precoder is able to achieve the theoretical sum capacity of downlink channel with perfect channel state information (CSI). However, the perfect CSI is not available at the transmitter in practical system, especially in frequency division duplex (FDD) system where the imperfect CSI is the delayed, quantized channel direction information relayed back from the receiver through a dedicated feedback channel. So the performance of conventional non-linear precoder degrades significantly. In this paper, a robust non-linear Tomlinson-Harashima precoding (THP) based on sum mean squared error (SMSE) minimization for the downlink of multiuser MISO FDD systems is proposed. The proposed precoder is robust to the channel uncertainties arising from channel delay and quantization error. Furthermore, an improved non-linear THP with channel magnitude information (CMI) consideration is introduced to compensate the instantaneous CMI shortage at the transmitter. Additionally, the computational complexity of both proposed precoders can be reduced remarkably by Cholesky factorization with symmetric permutation. Simulation results demonstrate the improvement in bit error ratio performance and illustrate the SMSE performance of the proposed algorithms compared with conventional THP with perfect CSI in the literature. [ABSTRACT FROM AUTHOR]