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
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.
