The preparation of nano sized La 2O 3 powder by mechanochemical reaction of lanthanum carbonate with sodium hydroxide and subsequent heat treatment was studied using X ray diffraction, differential thermal and ther...The preparation of nano sized La 2O 3 powder by mechanochemical reaction of lanthanum carbonate with sodium hydroxide and subsequent heat treatment was studied using X ray diffraction, differential thermal and thermo gravimetric analysis and transmission electron microscopy. It was found that the mechanochemical reaction process can be divided into two steps: the first step is the multi phases mechanochemical reaction of lanthanum carbonate with NaOH to form amorphous lanthanum basic carbonate and lanthanum hydroxide, and the second step is the crystallization of basic lanthanum carbonate with the formula of La 2(OH) 2(CO 3) 2·H 2O under a quasi hydrothermal synthesis condition caused by the mechanical ball milling. The synthesized La 2O 3 powder appears clearly separated spherical like monodisperse nano size particles in which particle size ranges from 30 to 50 nm.展开更多
The solvent-free reactions of aromatic ketones and aldehydes in the presence of Zn-ZnCl2 were performed with the aid of high-speed vibration mill, Retsch MM200 mixer mill and Retsch RM100 mortar grinder to give pinaco...The solvent-free reactions of aromatic ketones and aldehydes in the presence of Zn-ZnCl2 were performed with the aid of high-speed vibration mill, Retsch MM200 mixer mill and Retsch RM100 mortar grinder to give pinacol coupling and reduction products in varying yields.展开更多
Comprehensive Summary Polymer mechanochemistry on reactive species has attracted more and more attentions over the past 20 years,as the mechanochemical generation of reactive species has a great potential in developin...Comprehensive Summary Polymer mechanochemistry on reactive species has attracted more and more attentions over the past 20 years,as the mechanochemical generation of reactive species has a great potential in developing different polymeric materials for various purposes,such as stress detection,self-healing,self-strengthening,controllable degradation and release of small molecules.In this review,we first discuss the recent progress on polymer mechanochemistry of the reactive species that are generated from the mechanochemical reactions of mechanophores.Five types of reactive species,including radical,zwitterion,ionic,carbene and neutral intermediates,and their applications were reviewed in detail.Since mechanochemical reactions are sensitive to the mechanophore structure and polymer framework,we then discuss how mechanophore isomerism,polymer structure,polymer attachment point,and polymer architecture influence the mechanophore activation.At last,we provide our perspectives on the polymer mechanochemistry of reactivespecies.展开更多
Lithium metal batteries(LMBs)with high energy density are impeded by the instability of solid electrolyte interface(SEI)and the uncontrolled growth of lithium(Li)dendrite.To mitigate these challenges,optimizing the SE...Lithium metal batteries(LMBs)with high energy density are impeded by the instability of solid electrolyte interface(SEI)and the uncontrolled growth of lithium(Li)dendrite.To mitigate these challenges,optimizing the SEI structure and Li deposition behavior is the key to stable LMBs.This study novelty proposes a facile synthesis of MgF_(2)/carbon(C)nanocomposite through the mechanochemical reaction between metallic Mg and polytetrafluoroethylene(PTFE)powders,and its modified polypropylene(PP)separator enhances LMB performance.The in-situ formed highly conductive fluorine-doped C species play a crucial role in facilitating ion/electron transport,thereby accelerating electrochemical kinetics and altering Li deposition direction.During cycling,the in-situ reaction between MgF_(2)and Li leads to the formation of LiMg alloy,along with a LiF-rich SEI layer,which reduces the nucleation overpotential and reinforces the interphase strength,leading to homogeneous Li deposition with dendrite-free feature.Benefiting from these merits,the Li metal is densely and uniformly deposited on the MgF_(2)/C@PP separator side rather than on the current collector side.Furthermore,the symmetric cell with MgF_(2)/C@PP exhibits superb Li plating/stripping performance over 2800 h at 1 mA cm^(-2)and 2 mA h cm^(-2).More importantly,the assembled Li@MgF_(2)/C@PPILiFePO4full cell with a low negative/positive ratio of 3.6delivers an impressive cyclability with 82.7%capacity retention over 1400 cycles at 1 C.展开更多
Research on triboluminescence phenomena has been comprehensively reviewed,with a focus on the activation mechanisms resulting from the dissipation of mechanical energy at interfaces.The complexity and interdisciplinar...Research on triboluminescence phenomena has been comprehensively reviewed,with a focus on the activation mechanisms resulting from the dissipation of mechanical energy at interfaces.The complexity and interdisciplinary nature of this phenomenon,along with its dependence on gas composition and pressure,have been analyzed.Special attention was given to air,inert gases,polyatomic gases,and hydrocarbon gases.The influence of gas composition on triboluminescence is not straightforward.This is because at least three components are associated with different physical and chemical processes and activation mechanisms.These components include triboluminescence(TL)1:gas discharge luminescence.This occurs because of the generation of an electric field and dielectric breakdown of gases surrounding the mechanically activated zone of the material;TL2:photoluminescence of mechanically activated material.This results from the excitation of luminescent centers by the absorption of ultraviolet radiation from the gas discharge;TL3:material luminescence not related to photoluminescence.This is the least studied and most complex component.This can be related to the direct coupling of the mechanical force with the energy landscape of defects,impurities,and other centers.These centers can be excited and emit light during deexcitation.Other possibilities include luminescence excited by electric fields,exoelectron emission,etc.Therefore,the gas environment is crucial not only for gas discharge(as various gases can promote or quench it)but also for controlling other excitation and deexcitation processes.These processes occur through interactions of adsorbed films with stressed materials,tribochemical reactions,photochemical reactions,and so on.Furthermore,the potential application of triboluminescence for sensing gas composition is highlighted.展开更多
Achieving an in-depth understanding of the nexus between temperature and phase transitions is paramount for advancing the electrochemical efficiency of aqueous zinc ion batteries.Yet,the intricacies of electrochemical...Achieving an in-depth understanding of the nexus between temperature and phase transitions is paramount for advancing the electrochemical efficiency of aqueous zinc ion batteries.Yet,the intricacies of electrochemical interactions,particularly those associated with the structural evolution over extended periods,remain enigmatic.In this research,we leverage V_(2)O_(5) as an initial structural model of crystals to demystify the kinetics of electrode reactions and the decay mechanism of global electrochemical degradation by meticulously controlling the crystal defects via applying different mechanical grounding intensities.It is noted that the grounding V_(2)O_(5)(GVO)can exhibit a stable crystal structure that suppresses the dissolution/shuttling of vanadium and mitigates Zn anodes by-products caused by electrochemical processes.Thus,the GVO is utilized as the cathode material,achieving excellent Zn storage capacity at both room temperature and low temperatures,e.g.,380 and 246 mA h g^(−1) at room temperature and−20℃,respectively.Remarkably,the GVO cathode retains a specific capacity of 160 mA h g^(−1) with a capacity retention rate of 99%after 1500 cycles at−20℃ and 1 A g^(−1).This work provides a novel insight into the electrochemical crosstalk behavior of aqueous zinc-ion batteries(AZIBs)in a wide range of temperatures.展开更多
文摘The preparation of nano sized La 2O 3 powder by mechanochemical reaction of lanthanum carbonate with sodium hydroxide and subsequent heat treatment was studied using X ray diffraction, differential thermal and thermo gravimetric analysis and transmission electron microscopy. It was found that the mechanochemical reaction process can be divided into two steps: the first step is the multi phases mechanochemical reaction of lanthanum carbonate with NaOH to form amorphous lanthanum basic carbonate and lanthanum hydroxide, and the second step is the crystallization of basic lanthanum carbonate with the formula of La 2(OH) 2(CO 3) 2·H 2O under a quasi hydrothermal synthesis condition caused by the mechanical ball milling. The synthesized La 2O 3 powder appears clearly separated spherical like monodisperse nano size particles in which particle size ranges from 30 to 50 nm.
文摘The solvent-free reactions of aromatic ketones and aldehydes in the presence of Zn-ZnCl2 were performed with the aid of high-speed vibration mill, Retsch MM200 mixer mill and Retsch RM100 mortar grinder to give pinacol coupling and reduction products in varying yields.
基金support from the National Natural Science Foundation of China(22201198 and 21925107)funding from the Natural Science Foundation of JiangsuProvince(BK20220506).
文摘Comprehensive Summary Polymer mechanochemistry on reactive species has attracted more and more attentions over the past 20 years,as the mechanochemical generation of reactive species has a great potential in developing different polymeric materials for various purposes,such as stress detection,self-healing,self-strengthening,controllable degradation and release of small molecules.In this review,we first discuss the recent progress on polymer mechanochemistry of the reactive species that are generated from the mechanochemical reactions of mechanophores.Five types of reactive species,including radical,zwitterion,ionic,carbene and neutral intermediates,and their applications were reviewed in detail.Since mechanochemical reactions are sensitive to the mechanophore structure and polymer framework,we then discuss how mechanophore isomerism,polymer structure,polymer attachment point,and polymer architecture influence the mechanophore activation.At last,we provide our perspectives on the polymer mechanochemistry of reactivespecies.
基金financially supported by the Natural Science Foundation of China(52277218)the Hubei Provincial Natural Science Foundation of China(2024AFA094)+1 种基金the Excellent Discipline Cultivation Project by JHUN(2023XKZ009)the Graduate Student Innovation Fund of JHUN(KYCXJJ202422).
文摘Lithium metal batteries(LMBs)with high energy density are impeded by the instability of solid electrolyte interface(SEI)and the uncontrolled growth of lithium(Li)dendrite.To mitigate these challenges,optimizing the SEI structure and Li deposition behavior is the key to stable LMBs.This study novelty proposes a facile synthesis of MgF_(2)/carbon(C)nanocomposite through the mechanochemical reaction between metallic Mg and polytetrafluoroethylene(PTFE)powders,and its modified polypropylene(PP)separator enhances LMB performance.The in-situ formed highly conductive fluorine-doped C species play a crucial role in facilitating ion/electron transport,thereby accelerating electrochemical kinetics and altering Li deposition direction.During cycling,the in-situ reaction between MgF_(2)and Li leads to the formation of LiMg alloy,along with a LiF-rich SEI layer,which reduces the nucleation overpotential and reinforces the interphase strength,leading to homogeneous Li deposition with dendrite-free feature.Benefiting from these merits,the Li metal is densely and uniformly deposited on the MgF_(2)/C@PP separator side rather than on the current collector side.Furthermore,the symmetric cell with MgF_(2)/C@PP exhibits superb Li plating/stripping performance over 2800 h at 1 mA cm^(-2)and 2 mA h cm^(-2).More importantly,the assembled Li@MgF_(2)/C@PPILiFePO4full cell with a low negative/positive ratio of 3.6delivers an impressive cyclability with 82.7%capacity retention over 1400 cycles at 1 C.
基金support received from the Russian Science Foundation(Grant 23-12-20002)the Ministry of Science,Innovation and Universities of Spain(Grants PID2019-111063RB-I00 and TED2021-129950B-I00).
文摘Research on triboluminescence phenomena has been comprehensively reviewed,with a focus on the activation mechanisms resulting from the dissipation of mechanical energy at interfaces.The complexity and interdisciplinary nature of this phenomenon,along with its dependence on gas composition and pressure,have been analyzed.Special attention was given to air,inert gases,polyatomic gases,and hydrocarbon gases.The influence of gas composition on triboluminescence is not straightforward.This is because at least three components are associated with different physical and chemical processes and activation mechanisms.These components include triboluminescence(TL)1:gas discharge luminescence.This occurs because of the generation of an electric field and dielectric breakdown of gases surrounding the mechanically activated zone of the material;TL2:photoluminescence of mechanically activated material.This results from the excitation of luminescent centers by the absorption of ultraviolet radiation from the gas discharge;TL3:material luminescence not related to photoluminescence.This is the least studied and most complex component.This can be related to the direct coupling of the mechanical force with the energy landscape of defects,impurities,and other centers.These centers can be excited and emit light during deexcitation.Other possibilities include luminescence excited by electric fields,exoelectron emission,etc.Therefore,the gas environment is crucial not only for gas discharge(as various gases can promote or quench it)but also for controlling other excitation and deexcitation processes.These processes occur through interactions of adsorbed films with stressed materials,tribochemical reactions,photochemical reactions,and so on.Furthermore,the potential application of triboluminescence for sensing gas composition is highlighted.
基金supported by the Natural Science Foundation of Xiamen, China (3502Z202372036)the National Natural Science Foundation of China (52372191, 52073286 (to CZ Lu), 22275185 (to CZ Lu))+4 种基金the Scientific Research Funds of Huaqiao University (20221XD027, 20221XD045)the Xiamen Institute of Rare Earth Materials Haixi Institutes (XMIREM)the Autonomously Deployment Project (2023GG01 (to CZ Lu))the Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China (2021ZZ115 (to CZ Lu))the China Postdoctoral Science Foundation (2022TQ0282)。
文摘Achieving an in-depth understanding of the nexus between temperature and phase transitions is paramount for advancing the electrochemical efficiency of aqueous zinc ion batteries.Yet,the intricacies of electrochemical interactions,particularly those associated with the structural evolution over extended periods,remain enigmatic.In this research,we leverage V_(2)O_(5) as an initial structural model of crystals to demystify the kinetics of electrode reactions and the decay mechanism of global electrochemical degradation by meticulously controlling the crystal defects via applying different mechanical grounding intensities.It is noted that the grounding V_(2)O_(5)(GVO)can exhibit a stable crystal structure that suppresses the dissolution/shuttling of vanadium and mitigates Zn anodes by-products caused by electrochemical processes.Thus,the GVO is utilized as the cathode material,achieving excellent Zn storage capacity at both room temperature and low temperatures,e.g.,380 and 246 mA h g^(−1) at room temperature and−20℃,respectively.Remarkably,the GVO cathode retains a specific capacity of 160 mA h g^(−1) with a capacity retention rate of 99%after 1500 cycles at−20℃ and 1 A g^(−1).This work provides a novel insight into the electrochemical crosstalk behavior of aqueous zinc-ion batteries(AZIBs)in a wide range of temperatures.
