State Key Laboratory of Electrical Insulation and Power Equipment

Full-cell cycling of a high density silicon-majority anode with 2× volumetric capacity of graphite and a stabilized coulombic efficiency exceeding 99.9%.

New-generation integrated devices based on dye-sensitized and perovskite solar cells for energy harvesting and storage are significantly important for self-powering systems and portable/wearable electronics.

In this letter, we use transmission electron microscopy to study the microstructure feature of recently reported Pb-free piezoceramic Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 across its piezoelectricity-optimal morphotropic phase boundary (MPB) by varying composition and temperature, respectively. The domain structure evolutions during such processes show that in MPB regime, the domains become miniaturized down to nanometer size with a domain hierarchy, which coincides with the d33-maximum region. Further convergent beam electron diffraction measurement shows that rhombohedral and tetragonal crystal symmetries coexist among the miniaturized domains. Strong piezoelectricity reported in such a system is due to easy polarization rotation between the coexisting nano-scale tetragonal and rhombohedral domains.

Surface of BaTiO3 particle was chemically modified using silane coupling agent (KH550) in order to improve its compatibility with polyvinylidene fluoride (PVDF) matrix polymer, and therefore, expectable microstructure and dielectric property of the BaTiO3/PVDF composites were acquired. Infrared spectra reveal an obvious interaction between BaTiO3 and PVDF induced by the addition of KH550 coupling agent, and the interaction was also confirmed by the observation of morphology of fractured surface of the BaTiO3/PVDF composite when the concentration of KH550 is around 1.0wt%. Crystal lattice parameter of BaTiO3 in the composite was also changed because of the interaction. Finally, increased dielectric constant in the PVDF matrix composite with BaTiO3 treated by 1.0wt% KH550 was found.

g-C₃N₄ nanosheets are used as solid electrolyte filler for the first time.

Tuning local spin state of Co centres by Fe doping in cobalt–iron selenides is effective for boosting oxygen evolution.

Recently, a new two-dimensional material, single- or few-layered black phosphorus (BP), has attracted considerable attention for applications in electronics, optoelectronics, and batteries due to its unique properties, including large specific surface area, anisotropy, and tunable and direct band gaps. In particular, contributions to electrochemical energy storage devices, such as lithium and sodium ion batteries and supercapacitors, have emerged. However, critical issues remain to be explored before scaled-up commercial production of BP, such as preparation, stability, and performance. Herein, we present the first review of recent progress in BP-based electrochemical energy storage device. The preparation and electrochemical properties of black phosphorus, recent advances, potential challenges, and relevant perspectives in electrochemical energy storage, and the potential of BP are discussed in this work.

Abstract Lithium–sulfur batteries are currently being explored as promising advanced energy storage systems due to the high theoretical specific capacity of sulfur. However, achieving a scalable synthesis for the sulfur electrode material whilst maintaining a high volumetric energy density remains a serious challenge. Here, a continuous ball‐milling route is devised for synthesizing multifunctional FeS 2 /FeS/S composites for use as high tap density electrodes. These composites demonstrate a maximum reversible capacity of 1044.7 mAh g −1 and a peak volumetric capacity of 2131.1 Ah L −1 after 30 cycles. The binding direction is also considered here for the first time between dissolved lithium polysulfides (LiPSs) and host materials (FeS 2 and FeS in this work) as determined by density functional theory calculations. It is concluded that if only one lithium atom of the polysulfide bonds with the sulfur atoms of FeS 2 or FeS, then any chemical interaction between these species is weak or negligible. In addition, FeS 2 is shown to have a strong catalytic effect on the reduction reactions of LiPSs. This work demonstrates the limitations of a strategy based on chemical interactions to improve cycling stability and offers new insights into the development of high tap density and high‐performance sulfur‐based electrodes.

An ultrahigh enhancement rate of <italic>U</italic>_d (≈187%) and <italic>U</italic>_d (≈19 J cm⁻³) have been obtained for P(VDF-HFP)-based nanocomposites using novel core–shell BaTiO₃@MgO as the filler.

Stainless steel fiber (SSF)/poly(vinylidene fluoride) composite is prepared via simple blending and hot pressing route. The dependence of the dielectric properties of the composite on both volume fraction of the fillers and frequency is investigated. The percolation threshold of the composite, 9.4vol% (0.094 volume fraction), is much lower than that of the common two phase metal particle-polymer composite. A dielectric constant of 427 is observed at 50Hz with 10vol% of SSF. Large enhancements of the ac conductivity and loss tangent are also observed near the percolation threshold. The dielectric properties are explained by percolation theory while the dielectric anomalies are attributed to the high slenderness ratio of the SSF fillers.

The LTMN_0.25 + 1 wt% 0.6CuO–0.4B₂O₃ ceramic with low sintering temperature, small density and excellent performance have wide application prospects in 5G devices.

The mechanical properties and electrochemical stability of a PEO based composite solid polymer electrolyte are enhanced by adding MnO₂ nanosheets.

The piezoelectric activity of lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) ceramics has been investigated as a function of composition by using Rayleigh analysis under subswitching-electric-field in combination with large-electric-field strain measurement. The result shows that the intrinsic piezoelectric response exhibits peak values in the vicinity of composition-induced R (rhombohedral)-MPB (morphotropic phase boundary) and MPB-T (tetragonal) phase transitions, but being much less than total d33 value. On the other hand, the extrinsic piezoelectric response, especially the one associated with reversible domain wall motion, has been greatly enhanced in the phase instability regime. Our results indicate that the extrinsic piezoelectric activity is the major contributor to the high piezoelectricity in BZT-xBCT ceramics.

This paper proposes a novel Peer-to-Peer (P2P) joint electricity and carbon (E&C) trading model to co-optimize the energy and carbon emissions permit transactions considering the trading preferences in the distribution network. To realize the secure and low-carbon network operation, a decomposable carbon-aware distribution locational marginal pricing (CDLMP)-based operation service pricing scheme of the distribution system operator (DSO) is proposed to guide the P2P transactions among prosumers. In practice, the coordination between the P2P market and the DSO is cast as a bi-level optimization. In the upper level, the network operation optimization of the DSO is modeled as a carbon-aware optimal power flow (COPF) problem based on a carbon emission flow model to ensure the security of network operation and derive the CDLMP. In the lower level, a decentralized P2P joint E&C trading is modeled to simultaneously clear energy and carbon permit. Later, this paper develops an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">l</i> (p)-Box ADMM method to relax the binary variables originating from the peer-matching process of the carbon trading. Finally, a novel demurrage protocol is designed to facilitate the convergence of the bi-level interaction with an incentive for trading adjustments. Case studies illustrate the effectiveness of the proposed method in motivating “grid-friendly” and “low-carbon” P2P trading.

Lithium-rich anti-perovskites (LiRAPs) are a promising family of solid electrolytes, which exhibit ionic conductivities above 10(-3) S cm(-1) at room temperature, among the highest reported values to date. In this work, we investigate the defect chemistry and the associated lithium transport in Li3OCl, a prototypical LiRAP, using ab initio density functional theory (DFT) calculations and classical molecular dynamics (MD) simulations. We studied three types of charge neutral defect pairs, namely the LiCl Schottky pair, the Li2O Schottky pair, and the Li interstitial with a substitutional defect of O on the Cl site. Among them the LiCl Schottky pair has the lowest binding energy and is the most energetically favorable for diffusion as computed by DFT. This is confirmed by classical MD simulations, where the computed Li ion diffusion coefficients for LiCl Schottky systems are significantly higher than those for the other two defects considered and the activation energy in LiCl deficient Li3OCl is comparable to experimental values. The high conductivities and low activation energies of LiCl Schottky systems are explained by the low energy pathways of Li between the Cl vacancies. We propose that Li vacancy hopping is the main diffusion mechanism in highly conductive Li3OCl.

Lithium ion conductivity and mechanical strength of a PEO based composite solid polymer electrolyte are improved by adding h-BN.

High-impedance faults (HIFs) pose the greatest challenge for distribution system protection, especially for microgrids and distribution networks with distributed generators (DGs) that have flexible operation modes. This paper analyzes the faulty features of HIFs and proposes a HIF detection method that uses empirical wavelet transform (EWT) and differential faulty energy. The proposed method is as follows. First, the various time-frequency components are obtained by utilizing the EWT to decompose the differential faulty energy and adaptively select the feature component with the largest permutation entropy. Second, the permutation variance index is constructed based on the sample point number and feature component energy, and then it is employed to detect HIFs. Finally, low voltage microgrid simulation tests, medium voltage distribution system integrated by DG simulation tests, and field tests show that the proposed method can correctly distinguish HIFs from normal disturbances, including operation mode switches, load switches, capacitor switches, and DG switches. The advantages of the proposed method are also elaborated in detail, from signal preprocessing and feature extraction.

Solid Co nanoparticles were oxidized into hollow Co₃O₄ counterparts in the electrospun (carbon) nanofibers by annealing under ambient atmosphere, which showed superior lithium storage properties.

This paper proposes a novel high-order passive filter, i.e., series-parallel-resonant LCL (SPRLCL) filter, for single-phase half-bridge active power filters. The proposed SPRLCL filter consists of a series resonance introduced by adding a small inductor to the capacitor branch loop and a parallel resonance by paralleling a small capacitor with the gird-side inductor. Three design methods are proposed to fine tune the parameters of the SPRLCL filter. Design method I and method II enable the SPRLCL filter to attenuate more switching-frequency and double switching-frequency current harmonics than LCL or LLCL filters, while with design method III, the SPRLCL filter can be more robust against filter parameter variations. In order to achieve a better damping performance and facilitate the design of active damping control, the dominant resonance frequency of the proposed filter is set at one-third of the system sampling frequency. Based on this, a comprehensive parameter design process of the SPRLCL filter is presented, where the variation of source inductance is also considered. A proportional plus repetitive current-loop controller is designed to ensure system control stability and satisfactory harmonic compensation. Simulation and experimental results are finally presented to validate the feasibility of the theoretical analysis.

A novel flower-like In2S3/CdIn2S4/In2O3 (ICS) ternary heterostructure (HS) is rationally constructed for the first time by a series of carefully designed procedures. In2O3 nanoflakes are the main constituent units which assemble into a flower-like skeleton structure, and CdIn2S4 nanoparticles are in situ generated on the surface of In2O3 nanoflakes through the transformation of CdS quantum dots (QDs) while In2S3 nanoparticles are in situ produced at the region between CdIn2S4 nanoparticles and In2O3 nanoflakes resulting from a synchronous sulfuration procedure. As expected, the rationally designed ICS ternary HSs display significantly enhanced photocatalytic H2 production, especially ICS5 (sulfurized for 5 h) with the highest H2 evolution rate of 20.04 μmol h-1 (10 mg catalyst is used for photocatalytic reaction), which is 26.7 times and 2.6 times higher than that of pure In2O3 (0.75 μmol h-1) and In2S3/In2O3 binary HS (7.88 μmol h-1), respectively. The enhanced photocatalytic activity can be attributed to the multiple interfaces formed in the ICS HSs, including the CdIn2S4-In2O3 interface, the In2S3-In2O3 interface, and the CdIn2S4-In2O3-In2S3 interface, which construct multiple pathways for the transfer of photogenerated charge carriers, effectively promoting the photocatalytic hydrogen production.