Revealing the origin of improved reversible capacity of dual-shell bismuth boxes anode for potassium-Ion batteries

Nanostructured alloy anodes have been successfully used in several kinds of rocking-chair batteries. However, a full picture of the origin of their improved reversible capacity remains elusive. Here, we combine operando synchrotron-based X-ray powder diffraction and ex situ X-ray absorption near-edge structure spectroscopy to study the double-shell structured bismuth boxes as anodes in potassium-ion batteries to reveal the origin of their improved capacity. The nanostructured bismuth anode offers an enhanced capability to tolerate the volume expansion under a low current density of 0.2 C, resulting in a more complete alloy reaction. Additionally, under a high current density of 2 C, nanostructured bismuth anode with larger surface area offers more sites to electrochemically alloy with potassium and results in a lower average oxidation state of bismuth. These findings offer guidance for the rational design and engineering of electrode materials according to the current density for rocking-chair batteries.Fangxi Xie, Lei Zhang, Biao Chen, Dongliang Chao, Qinfen Gu, Bernt Johannessen, Mietek Jaroniec, and Shi-Zhang Qia

Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV

Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7  fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale

Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV

Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values

Toward high-voltage aqueous batteries: super- or low-concentrated electrolyte?

Abstract not available.Dongliang Chao and Shi-Zhang Qia

Transition metal dichalcogenides for alkali metal ion batteries: engineering strategies at the atomic level

In the past few decades, great effort has been made toward the preparation and development of advanced transition metal dichalcogenide (TMD) materials for anodes of alkali metal ion batteries (AMIBs). However, their electrochemical performance is still severely impaired by structural aggregation and fracture during the conversion reaction. To address these issues, various methodologies for the fabrication of hierarchical and hybrid nanostructures, with optimization of materials and electrodes, have been fully investigated and reviewed. As regards tuning the TMD-based materials, extensive efforts have been undertaken toward optimization of their intrinsic structure at the atomic level, including surface defects, interlayer spacing expansion, phase control, alloying, and heteroatom doping. However, the design strategies and methods to manipulate the intrinsic structures and electrochemical mechanisms in AMIBs have not been fully summarized. This review provides a well-timed and critical appraisal of recent advances in the engineering of TMDs at the atomic level for AMIBs, by combining computational and experimental approaches. The correlation between these strategies and electrochemical performance is highlighted. The challenges and opportunities in this research field are also outlined. We expect that this review would be beneficial for improving the overall knowledge on the charge storage mechanisms in TMDs and for pointing out the importance of intrinsic structure engineering for enhancing the performance of TMDs in energy storage.Biao Chen, Dongliang Chao, Enzuo Liu, Mietek Jaroniec, Naiqin Zhao and Shi-Zhang Qia

Unveiling the advances of 2D materials for Li/Na-S batteries experimentally and theoretically

Metal-sulfur batteries hold practical promise for next-generation batteries because of high energy density and low cost. Development is impeded at present, however, because of unsatisfied discharge capacity and stability in long cycling. Combination of experimental and theoretical approaches can be used to develop insight into the relationship between electrochemical behavior of sulfur redox and metal stripping-plating and the structural properties of electrode materials. With metal-sulfur batteries, two-dimensional (2D) nanomaterials are a suitable model with which to connect and test experimental results with theoretical predictions and to explore structure-property relationships. Here, through the view of combining experimental and theoretical approaches, we explore sulfur redox conversion on 2D nanomaterials in various reaction stages and critically review crucial factors affecting 2D nanomaterials as artificial solid electrolyte interfaces (SEIs) and host materials in protecting Li and Na metal anodes. We conclude with a focused discussion on promising research orientations for developing high-performance metal-sulfur batteries.Chao Ye, Dongliang Chao, Jieqiong Shan, Huan Li, Kenneth Davey, and Shi-Zhang Qia

Mechanism for zincophilic sites on zinc-metal anode hosts in aqueous batteries

The zinc‐metal anode (ZMA) is a critical component of rechargeable Zn‐based batteries. Zinc‐dendrite formation on ZMA during cycling causes an internal short‐circuit, thereby limiting long‐term practical operation of batteries. A strategy of introducing zincophilic sites shows promise in suppressing dendrite growth. However, the mechanism is not understood. Here, a detailed study of the mechanism of zincophilic sites based on multiple in situ/ex situ techniques is reported. Using a carbon‐host as a model system with nitrogen sites as zincophilic sites and both ex situ near‐edge X‐ray absorption fine structure (NEXAFS) and in situ Raman spectra, it is shown that zinc ions are bonded with pyridine sites to form Zn–N bonds. The Zn–N bonds induce spacious nucleation of zinc on carbon‐hosts and suppress zinc‐dendrite formation. The host with zincophilic sites exhibits a homogenous Zn deposition, together with boosted electrochemical performance. This finding underscores the impact of nitrogen zincophilic sites in suppressing zinc‐dendrite formation. It is shown that bonding between zinc ions and zincophilic sites is the mechanism for zincophilic nucleation in the ZMA host. These findings are expected to be of immediate benefit to researchers in battery technologies and materials science.Fangxi Xie, Huan Li, Xuesi Wang, Xing Zhi, Dongliang Chao, Kenneth Davey, and Shi-Zhang Qia

An electrolytic Zn-MnO(2) battery for high-voltage and scalable energy storage

Zinc-based electrochemistry is attracting significant attention for practical energy storage owing to its uniqueness in terms of low cost and high safety. However, the grid-scale application is plagued by limited output voltage and inadequate energy density when compared with more conventional Li-ion batteries. Herein, we propose a latent high-voltage MnO2 electrolysis process in a conventional Zn-ion battery, and report a new electrolytic Zn-MnO2 system, via enabled proton and electron dynamics, that maximizes the electrolysis process. Compared with other Zn-based electrochemical devices, this new electrolytic Zn-MnO2 battery has a record-high output voltage of 1.95 V and an imposing gravimetric capacity of about 570 mAh g-1 , together with a record energy density of approximately 409 Wh kg-1 when both anode and cathode active materials are taken into consideration. The cost was conservatively estimated at <US$ 10 per kWh. This result opens a new opportunity for the development of Zn-based batteries, and should be of immediate benefit for low-cost practical energy storage and grid-scale applications.Dongliang Chao, Wanhai Zhou, Chao Ye, Qinghua Zhang, Yungui Chen, Lin Gu, Kenneth Davey, Shi‐Zhang Qia