The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered...The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.展开更多
Ti-bearing slag(TiO2>20 wt%)is a valuable titanium secondary resource.The extraction of titanium from the slag is difficult due to the complex composition and structure.Although molten oxide electrolysis is conside...Ti-bearing slag(TiO2>20 wt%)is a valuable titanium secondary resource.The extraction of titanium from the slag is difficult due to the complex composition and structure.Although molten oxide electrolysis is considered as a promising method,silicon will be preferentially electroreduced compared to titanium due to low theoretical decomposition voltage.In this work,a liquid copper cathode is used to selectively extract titanium from molten Al2O3-MgO-CaO-TiO2-SiO2 electrolyte.It is found that comparing to silicon,titanium can be preferentially reduced by one-step electron transfer due to the enhanced depolarization effect on a liquid copper cathode.So,Ti-Cu alloys are firstly obtained from molten Ti-bearing slag,and then Ti-Si alloys are co-electrodeposited in the molten oxide electrolyte with low TiO2 content.It may be ascribed to the larger binding force between titanium and copper than that between silicon and copper.It provides an effective strategy for the separation of titanium from of Ti-bearing slag.展开更多
Rechargeable Al-ion batteries(AIBs)are considered as one of the most fascinating energy storage systems due to abundant Al resource and low cost.However,the cycling stability is subjected to critical problems for usin...Rechargeable Al-ion batteries(AIBs)are considered as one of the most fascinating energy storage systems due to abundant Al resource and low cost.However,the cycling stability is subjected to critical problems for using Al foil as negative electrode,including Al dendrites,corrosion and pulverization.For addressing these problems,here a lightweight self-supporting N-doped carbon rod array(NCRA)is demonstrated for a long-life negative electrode in AIBs.Experimental analysis and first-principle calculations reveal the storage mechanism involving the induced deposition of N-containing function groups to Al as well as the ideal skeleton of the NCRA matrix for Al plating/stripping,which is favorable for regulating Al nucleation and suppressing dendrites growth.Compared with the Al foil,the NCRA exhibits lower areal mass density(∼72%of Al foil),smaller thickness(40%of Al foil),but much longer cycle life(>4 times of Al foil).Benefiting from the remarkable stability of the array structure,symmetric cells show excellent cycling stability with small voltage hysteresis(∼80 mV)and meanwhile there are no corrosion and pulverization problems even after cycled for 120 hours.Besides,full cells also manifest long lifespan(1,500 cycles)and increased Coulombic efficiency(100±1%).展开更多
基金National Natural Science Foundation of China(52104294)Fundamental Research Funds for the Central Universities(FRF-TP-19-079A1)。
文摘The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.
基金supported by the National Natural Science Foundation of China(51725401)the Fundamental Research Funds for the Central Universities(FRF-TP-18-010B1).
文摘Ti-bearing slag(TiO2>20 wt%)is a valuable titanium secondary resource.The extraction of titanium from the slag is difficult due to the complex composition and structure.Although molten oxide electrolysis is considered as a promising method,silicon will be preferentially electroreduced compared to titanium due to low theoretical decomposition voltage.In this work,a liquid copper cathode is used to selectively extract titanium from molten Al2O3-MgO-CaO-TiO2-SiO2 electrolyte.It is found that comparing to silicon,titanium can be preferentially reduced by one-step electron transfer due to the enhanced depolarization effect on a liquid copper cathode.So,Ti-Cu alloys are firstly obtained from molten Ti-bearing slag,and then Ti-Si alloys are co-electrodeposited in the molten oxide electrolyte with low TiO2 content.It may be ascribed to the larger binding force between titanium and copper than that between silicon and copper.It provides an effective strategy for the separation of titanium from of Ti-bearing slag.
基金We acknowledge financial support from the National Natural Science Foundation of China(Nos.51725401 and 51874019)the Fundamental Research Funds for the Central Universities(No.FRF-TP-17-002C2).
文摘Rechargeable Al-ion batteries(AIBs)are considered as one of the most fascinating energy storage systems due to abundant Al resource and low cost.However,the cycling stability is subjected to critical problems for using Al foil as negative electrode,including Al dendrites,corrosion and pulverization.For addressing these problems,here a lightweight self-supporting N-doped carbon rod array(NCRA)is demonstrated for a long-life negative electrode in AIBs.Experimental analysis and first-principle calculations reveal the storage mechanism involving the induced deposition of N-containing function groups to Al as well as the ideal skeleton of the NCRA matrix for Al plating/stripping,which is favorable for regulating Al nucleation and suppressing dendrites growth.Compared with the Al foil,the NCRA exhibits lower areal mass density(∼72%of Al foil),smaller thickness(40%of Al foil),but much longer cycle life(>4 times of Al foil).Benefiting from the remarkable stability of the array structure,symmetric cells show excellent cycling stability with small voltage hysteresis(∼80 mV)and meanwhile there are no corrosion and pulverization problems even after cycled for 120 hours.Besides,full cells also manifest long lifespan(1,500 cycles)and increased Coulombic efficiency(100±1%).
