将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析...将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析。Si 4+掺杂不仅可降低材料的锂镍混排程度,还能增强结构稳定性,且不会改变材料的形貌。以40 mA/g(0.2 C)的电流在2.5~4.5 V充放电,LiNi 0.47 Si 0.03 Mn 0.5 O 2(x=0.03)正极材料具有最好的电化学性能,不仅比容量(149.25 mAh/g)较未掺杂材料(125.44 mAh/g)提高20%,而且容量保持率在120次循环后也提高了7.7%。Si 4+掺杂能降低材料的锂镍混排程度,有利于Li+的迁移;能提高材料的结构稳定性,抑制电压的下降并减轻极化。展开更多
Layered Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) cathode materials for lithium-ion batteries were synthesized by one step solid-state method using Ni(OH)2, MnCO3, Li2CO3, TiO2 and Al(OH)3 as starting materials. The...Layered Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) cathode materials for lithium-ion batteries were synthesized by one step solid-state method using Ni(OH)2, MnCO3, Li2CO3, TiO2 and Al(OH)3 as starting materials. The effect of Ti and Al doping on the structure and electrochemical performance of Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) has been investigated. LiNi0.5Mn0.5O2, Li(Ni0.5Mn0.5)0.98Ti0.02O2 and Li(Ni0.5Mn0.5)0.98Al0.02O2 delivered 149 mAh·g-1, 160 mAh·g-1, 164 mAh·g-1, respectively, at a current of 20 mA·g-1 between 2.5 V and 4.3 V at room temperature, and remained 86%, 91%, 91% of the initial discharge capacity respectively after 30 cycles. AC impedance studies show that Ti and Al doping in Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) decreased the resistance of charge transfer Rct of cathode materials.展开更多
One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stabi...One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.展开更多
Spinel-structured LiNi_(0.5)Mn1.5O_(4) cathodes in lithium-ion batteries have gained attention for their high operating voltage,which provides high energy density,and their cost advantages due to the absence of cobalt...Spinel-structured LiNi_(0.5)Mn1.5O_(4) cathodes in lithium-ion batteries have gained attention for their high operating voltage,which provides high energy density,and their cost advantages due to the absence of cobalt.However,issues such as low cycle and thermal stabilities have been identified,with side reactions occurring at the electrode/electrolyte interface during continuous charge/discharge cycles that degrade electrode performance.Herein,we first optimized LiNi_(0.5)Mn1.5O_(4) using the Pechini sol–gel method to achieve uniform particles and controlled calcination temperatures.We then employed density functional theory and electrochemical testing to identify the optimal conditions.Uniform coating of the electrode surface with the oxide solid electrolyte Li_(6.28)Al_(0.24)La_(3)Zr_(2)O_(12)(LALZO)was confirmed,aiming to improve lithium-ion conductivity and enhance cycle and thermal stability.As a result,the formation of a coating layer on the electrode surface suppressed side reactions with the electrolyte and blocked contact,leading to an increase in ion conductivity.This improvement resulted in an enhanced rate capability and a significant increase in retention over 100 cycles at 0.2 C.Additionally,the interface resistance significantly improved with the coating layer,demonstrating reduced voltage decay due to overvoltage and improved interface stability.Finally,thermal stability was enhanced,with retention improving after 100 cycles at 0.5 C.展开更多
文摘将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析。Si 4+掺杂不仅可降低材料的锂镍混排程度,还能增强结构稳定性,且不会改变材料的形貌。以40 mA/g(0.2 C)的电流在2.5~4.5 V充放电,LiNi 0.47 Si 0.03 Mn 0.5 O 2(x=0.03)正极材料具有最好的电化学性能,不仅比容量(149.25 mAh/g)较未掺杂材料(125.44 mAh/g)提高20%,而且容量保持率在120次循环后也提高了7.7%。Si 4+掺杂能降低材料的锂镍混排程度,有利于Li+的迁移;能提高材料的结构稳定性,抑制电压的下降并减轻极化。
文摘Layered Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) cathode materials for lithium-ion batteries were synthesized by one step solid-state method using Ni(OH)2, MnCO3, Li2CO3, TiO2 and Al(OH)3 as starting materials. The effect of Ti and Al doping on the structure and electrochemical performance of Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) has been investigated. LiNi0.5Mn0.5O2, Li(Ni0.5Mn0.5)0.98Ti0.02O2 and Li(Ni0.5Mn0.5)0.98Al0.02O2 delivered 149 mAh·g-1, 160 mAh·g-1, 164 mAh·g-1, respectively, at a current of 20 mA·g-1 between 2.5 V and 4.3 V at room temperature, and remained 86%, 91%, 91% of the initial discharge capacity respectively after 30 cycles. AC impedance studies show that Ti and Al doping in Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti, Al; x=0, 0.02) decreased the resistance of charge transfer Rct of cathode materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52164029,52074099 and 52464033)Natural Science Foundation of Hainan Province(Nos.221RC585,821MS0782,221MS048 and 221RC 1072)+1 种基金Hainan Province Science and Technology Special Fund(Nos.ZDYF2022GXJS004 and ZDYF2021GXJS028)Scientific Research Foundation of Hainan Tropical Ocean University(No.RHDRC202112)
文摘One prominent cathode material utilized in commercial sodium-ion batteries is the O3-type NaNi_(0.5)Mn_(0.5)O_(2).The application of this material is hindered by multistage phase transitions and insufficient air stability.In this study,an innovative O3-type NaNi_(0.5)Mn_(0.5)O_(2),derived from Ni-MOFs (referred to as M-NNMO),has been developed as a cathode material for sodium-ion batteries.The M-NNMO cathode exhibits a discharge specific capacity of 124 mAh·g^(-1)at a rate of0.1C within 2.0 to 4.0 V.Furthermore,this material demonstrates an impressive capacity retention of 75%after undergoing 100 cycles.Complex phase transitions can be inhibited and ion diffusion rates can be increased simultaneously by Ni-MOFs through the enhancement of transition metal-oxygen bonding and the rise n Na layer gap,which are in charge of the remarkable performance improvement.Importantly,the enhanced stability of the M-NNMO transition metal layer based on the uniquestructural properties of Ni-MOFs in air stability tests.This work will provide theoretical guidance to design sodiumion battery cathode materials with superior performance.
基金supported by the National Research Foundation of Korea(NRF)(No.2020R1A2C2010510,2020R1A6A1A03044977).
文摘Spinel-structured LiNi_(0.5)Mn1.5O_(4) cathodes in lithium-ion batteries have gained attention for their high operating voltage,which provides high energy density,and their cost advantages due to the absence of cobalt.However,issues such as low cycle and thermal stabilities have been identified,with side reactions occurring at the electrode/electrolyte interface during continuous charge/discharge cycles that degrade electrode performance.Herein,we first optimized LiNi_(0.5)Mn1.5O_(4) using the Pechini sol–gel method to achieve uniform particles and controlled calcination temperatures.We then employed density functional theory and electrochemical testing to identify the optimal conditions.Uniform coating of the electrode surface with the oxide solid electrolyte Li_(6.28)Al_(0.24)La_(3)Zr_(2)O_(12)(LALZO)was confirmed,aiming to improve lithium-ion conductivity and enhance cycle and thermal stability.As a result,the formation of a coating layer on the electrode surface suppressed side reactions with the electrolyte and blocked contact,leading to an increase in ion conductivity.This improvement resulted in an enhanced rate capability and a significant increase in retention over 100 cycles at 0.2 C.Additionally,the interface resistance significantly improved with the coating layer,demonstrating reduced voltage decay due to overvoltage and improved interface stability.Finally,thermal stability was enhanced,with retention improving after 100 cycles at 0.5 C.
