随着电动汽车的发展,迫切需要具有高安全性、高能量密度、高功率、大容量、长寿命、高环保、低成本等优点的锂离子电池。层状结构的富锂锰基正极材料由于具有比容量高、平台电压高、热稳定性好、价格低廉的特点而被认为是有希望的未来...随着电动汽车的发展,迫切需要具有高安全性、高能量密度、高功率、大容量、长寿命、高环保、低成本等优点的锂离子电池。层状结构的富锂锰基正极材料由于具有比容量高、平台电压高、热稳定性好、价格低廉的特点而被认为是有希望的未来电动汽车候选正极材料之一。尽管其拥有很高的比容量,但仍存在着首次循环不可逆容量高、倍率性能差等问题,纳米化是改进材料倍率性能的一种有效手段。本文以Ni O,Co_3O_4,Mn CO_3和Li_2CO_3为原料,成功制备得到了纳米级的锂离子电池正极材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和充放电测试对所得样品的结构、形貌及电化学性能进行了表征。结果表明,合成的Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2材料具有层状结构,一次颗粒均匀、细小,平均颗粒尺寸约为90 nm,并具有良好的电化学性能,在2.0~4.8 V以0.1C充放电时,首次放电比容量达到284 m Ah·g^(-1),首次库伦效率为86.1%。材料同时拥有良好的倍率性能,1.0C放电容量达到240 m Ah·g^(-1),3.0C放电容量达到210 m Ah·g^(-1)。展开更多
利用XRD、SEM、EDS、BET、激光粒度、循环伏安、恒流充放电、交流阻抗方法研究了葡萄糖为碳源对溶胶凝胶法制备Li1.2Ni0.13Co0.13Mn0.54O2正极材料的结构、形貌以及电化学性能的影响。结果表明:与前驱体中未加入葡萄糖所制备的材料相比...利用XRD、SEM、EDS、BET、激光粒度、循环伏安、恒流充放电、交流阻抗方法研究了葡萄糖为碳源对溶胶凝胶法制备Li1.2Ni0.13Co0.13Mn0.54O2正极材料的结构、形貌以及电化学性能的影响。结果表明:与前驱体中未加入葡萄糖所制备的材料相比,掺葡萄糖后样品颗粒分布相对均匀,粒径变小,D50从11.56减小至9.94μm,比表面积增加近1倍。经0.05C充放电活化后,未掺葡萄糖和掺葡萄糖样品0.2C放电比容量分别为183.4、211.6 m Ah·g-1,2C容量分别为其0.2C的62.2%、77.6%。1C循环50次后放电比容量分别为133.3、173.6 m Ah·g-1,容量保持率分别为95.1%、100%。掺葡萄糖可降低首次不可逆容量损失,提高材料的倍率性能与循环稳定性,减少电荷传递阻抗、Warburg阻抗以及双电层弥散效应,但不改变材料的晶型结构。展开更多
以乙酸盐(乙酸锂、乙酸钠、乙酸钴、乙酸镍、乙酸锰等)为原材料,采用球磨辅助高温固相法制备Li_(1.0)Na_(0.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2正极材料。借助XRD、SEM等表征材料的结构和形貌,利用循环伏安、恒流充放电、交流阻抗等方法...以乙酸盐(乙酸锂、乙酸钠、乙酸钴、乙酸镍、乙酸锰等)为原材料,采用球磨辅助高温固相法制备Li_(1.0)Na_(0.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2正极材料。借助XRD、SEM等表征材料的结构和形貌,利用循环伏安、恒流充放电、交流阻抗等方法研究材料的电化学性能。结果表明,钠的掺杂导致颗粒表面光滑度降低,形成Na_(0.77)Mn O_(2.05)新相。0.05C活化过程中,掺钠样品和未掺钠样品首次放电比容量分别为258.4 m Ah·g^(-1)和215.8 m Ah·g^(-1),库伦效率分别为75.2%和72.8%;2C放电比容量分别为116.3 m Ah·g^(-1)和106.2 m Ah·g^(-1)。研究发现,掺钠可减小首次充放电过程的不可逆容量,提高容量保持率;改善倍率性能与容量恢复特性;降低SEI膜阻抗和电荷转移阻抗;掺钠后样品首次循环就可以基本完成Li_2Mn O_3组分向稳定结构的转化,而未掺杂的样品需要两次循环才能逐步完成该过程;XPS结果表明,掺钠样品中Ni^(2+)、Co^(3+)、Mn^(4+)所占比例明显提高,改善了样品的稳定性和电化学性能;循环200次后的XRD结果表明掺钠与未掺钠材料在脱嵌锂反应中的相变化过程基本一致,良好有序的层状结构遭到破坏是循环过程中容量衰减的主要原因。展开更多
将前驱体Ni0.13Co0.13Mn0.54（OH）1.6与Li2CO3混合,烧结合成了富锂锰基正极材料Li[LixNi0.13Co0.13Mn0.54]O2（x=0.09,0.12,0.16,0.22,0.24,0.29,0.33,0.37）,采用XRD、SEM对其进行表征,并进行充放电测试。研究结果表明：最佳配锂量为x...将前驱体Ni0.13Co0.13Mn0.54（OH）1.6与Li2CO3混合,烧结合成了富锂锰基正极材料Li[LixNi0.13Co0.13Mn0.54]O2（x=0.09,0.12,0.16,0.22,0.24,0.29,0.33,0.37）,采用XRD、SEM对其进行表征,并进行充放电测试。研究结果表明：最佳配锂量为x=0.22,此时Li1.22Ni0.133Co0.131Mn0.54O2正极材料以12.5 m A/g的充放电电流密度,在2~4.8 V之间进行电性能测试,初始放电比容量高达253.7 m Ah/g,首次效率为68.4%。展开更多
以过渡金属硫酸盐和一水合氢氧化锂为原料,采用共沉淀-高温固相烧结法制备富锂正极材料Li[Li0.2Ni0.13Co0.13Mn0.54]O2。通过XRD、SEM和电池充放电测试方法考察了产物结构和性能,结果表明：在水浴50℃下控制p H=11合成的前驱体具有很好...以过渡金属硫酸盐和一水合氢氧化锂为原料,采用共沉淀-高温固相烧结法制备富锂正极材料Li[Li0.2Ni0.13Co0.13Mn0.54]O2。通过XRD、SEM和电池充放电测试方法考察了产物结构和性能,结果表明：在水浴50℃下控制p H=11合成的前驱体具有很好的分散性,且在950℃下烧结得到了优越的电化学性能;在0.1C（1C=300 m A/g）充放电时,首次放电比容量为258.9 m Ah/g（2.0~4.8 V）,首次充放电效率为75.6%;在1C充放电时,首次放电比容量为204.6 m Ah/g,循环10次后放电比容量为179.9 m Ah/g;2C倍率下仍保持了141.4 m Ah/g的放电比容量。展开更多
富锂材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54-x)Zr_xO_2(x=0,0.02,0.05,0.1)是采用高温固相法合成,研究中采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外吸收光谱(FTIR)及电化学方法等手段进行了表征。实验结果表明,随着Zr含量...富锂材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54-x)Zr_xO_2(x=0,0.02,0.05,0.1)是采用高温固相法合成,研究中采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外吸收光谱(FTIR)及电化学方法等手段进行了表征。实验结果表明,随着Zr含量增加,材料的晶胞参数发生较大变化,Zr的掺杂抑制了Li1.2Ni0.13Co0.13Mn0.54O2高温合成时Mn3+的产生,有利于锂离子的可逆脱嵌,所合成富锂材料的粒径分布均匀,结晶性较佳。此外,电特性测试结果表明,Li1.2Ni0.13Co0.13Mn0.49Zr0.05O2富锂材料具有较佳的电性能,0.1 C下放电比容量达366 m Ah/g,循环100次后放电比容量保持率为96%。展开更多
Due to the low cost,high working voltage and high storage capacity,Li-rich Mn-based layered compounds show promise as the cathode materials for lithiumion batteries(LIBs).However,the side reactions at the solid-liquid...Due to the low cost,high working voltage and high storage capacity,Li-rich Mn-based layered compounds show promise as the cathode materials for lithiumion batteries(LIBs).However,the side reactions at the solid-liquid interface of the cathode will lead to rapid capacity decay and inferior rate performance.Herein,this article proposes a liquid-phase dispersion strategy to introduce a Na_(2)WO_(4)layer on the Li_(1.2)Ni_(0.13)-Co_(0.13)Mn_(0.54)O_(2) cathode,which can reduce the side effects between raw materials and electrolyte and promote the insertion/extraction rate of Li^(+),thus enhancing the material stability and rate performance.As a result,the capacity retention rate is 96.9%after 200 cycles under 2C.Moreover,the capacities are 177.5,149.5,111.1 and58.3 mAh·g^(-1)at 1C,2C,5C and 10C,implying a superior fast charging performance.The exceptional performance can be ascribed to both the increased conductivity and enhanced structural stability of the cathode material.What's more,based on the investigation of ion insertion/extraction behavior in electrode materials and the ion migration kinetics in the electrolyte,this study suggests that coating Li-rich Mn-based materials with Na_(2)WO_(4)can be a promising strategy to improve their performance in LIBs.展开更多
Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle ...Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle performance and poor rate property hinder its large-scale application.The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate.In this study,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2) is modified by using Li_(1.4)Al_(0.4)Ti_(1.6)(PO_(4))_(3)(LATP)ionic conductor.The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C,with a capacity retention of 81%.Compared with the uncoated pristine LRNCM(188.4 m A·h/g and 76%),LRNCM after the LATP modification shows superior cycle performance.Moreover,the lithium-ion diffusion coefficient D_(Li+)is a crucial factor affecting the rate performance,and the D_(Li+)of the LRNCM material is improved from 4.94×10^(-13) to 5.68×10^(-12)cm^(2)/s after modification.The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C,with an improved rate performance.Thus,the modification layer can considerably enhance the electrochemical performance of LRNCM.展开更多
文摘随着电动汽车的发展,迫切需要具有高安全性、高能量密度、高功率、大容量、长寿命、高环保、低成本等优点的锂离子电池。层状结构的富锂锰基正极材料由于具有比容量高、平台电压高、热稳定性好、价格低廉的特点而被认为是有希望的未来电动汽车候选正极材料之一。尽管其拥有很高的比容量,但仍存在着首次循环不可逆容量高、倍率性能差等问题,纳米化是改进材料倍率性能的一种有效手段。本文以Ni O,Co_3O_4,Mn CO_3和Li_2CO_3为原料,成功制备得到了纳米级的锂离子电池正极材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和充放电测试对所得样品的结构、形貌及电化学性能进行了表征。结果表明,合成的Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2材料具有层状结构,一次颗粒均匀、细小,平均颗粒尺寸约为90 nm,并具有良好的电化学性能,在2.0~4.8 V以0.1C充放电时,首次放电比容量达到284 m Ah·g^(-1),首次库伦效率为86.1%。材料同时拥有良好的倍率性能,1.0C放电容量达到240 m Ah·g^(-1),3.0C放电容量达到210 m Ah·g^(-1)。
文摘利用XRD、SEM、EDS、BET、激光粒度、循环伏安、恒流充放电、交流阻抗方法研究了葡萄糖为碳源对溶胶凝胶法制备Li1.2Ni0.13Co0.13Mn0.54O2正极材料的结构、形貌以及电化学性能的影响。结果表明:与前驱体中未加入葡萄糖所制备的材料相比,掺葡萄糖后样品颗粒分布相对均匀,粒径变小,D50从11.56减小至9.94μm,比表面积增加近1倍。经0.05C充放电活化后,未掺葡萄糖和掺葡萄糖样品0.2C放电比容量分别为183.4、211.6 m Ah·g-1,2C容量分别为其0.2C的62.2%、77.6%。1C循环50次后放电比容量分别为133.3、173.6 m Ah·g-1,容量保持率分别为95.1%、100%。掺葡萄糖可降低首次不可逆容量损失,提高材料的倍率性能与循环稳定性,减少电荷传递阻抗、Warburg阻抗以及双电层弥散效应,但不改变材料的晶型结构。
文摘以乙酸盐(乙酸锂、乙酸钠、乙酸钴、乙酸镍、乙酸锰等)为原材料,采用球磨辅助高温固相法制备Li_(1.0)Na_(0.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2正极材料。借助XRD、SEM等表征材料的结构和形貌,利用循环伏安、恒流充放电、交流阻抗等方法研究材料的电化学性能。结果表明,钠的掺杂导致颗粒表面光滑度降低,形成Na_(0.77)Mn O_(2.05)新相。0.05C活化过程中,掺钠样品和未掺钠样品首次放电比容量分别为258.4 m Ah·g^(-1)和215.8 m Ah·g^(-1),库伦效率分别为75.2%和72.8%;2C放电比容量分别为116.3 m Ah·g^(-1)和106.2 m Ah·g^(-1)。研究发现,掺钠可减小首次充放电过程的不可逆容量,提高容量保持率;改善倍率性能与容量恢复特性;降低SEI膜阻抗和电荷转移阻抗;掺钠后样品首次循环就可以基本完成Li_2Mn O_3组分向稳定结构的转化,而未掺杂的样品需要两次循环才能逐步完成该过程;XPS结果表明,掺钠样品中Ni^(2+)、Co^(3+)、Mn^(4+)所占比例明显提高,改善了样品的稳定性和电化学性能;循环200次后的XRD结果表明掺钠与未掺钠材料在脱嵌锂反应中的相变化过程基本一致,良好有序的层状结构遭到破坏是循环过程中容量衰减的主要原因。
文摘将前驱体Ni0.13Co0.13Mn0.54（OH）1.6与Li2CO3混合,烧结合成了富锂锰基正极材料Li[LixNi0.13Co0.13Mn0.54]O2（x=0.09,0.12,0.16,0.22,0.24,0.29,0.33,0.37）,采用XRD、SEM对其进行表征,并进行充放电测试。研究结果表明：最佳配锂量为x=0.22,此时Li1.22Ni0.133Co0.131Mn0.54O2正极材料以12.5 m A/g的充放电电流密度,在2~4.8 V之间进行电性能测试,初始放电比容量高达253.7 m Ah/g,首次效率为68.4%。
文摘以过渡金属硫酸盐和一水合氢氧化锂为原料,采用共沉淀-高温固相烧结法制备富锂正极材料Li[Li0.2Ni0.13Co0.13Mn0.54]O2。通过XRD、SEM和电池充放电测试方法考察了产物结构和性能,结果表明：在水浴50℃下控制p H=11合成的前驱体具有很好的分散性,且在950℃下烧结得到了优越的电化学性能;在0.1C（1C=300 m A/g）充放电时,首次放电比容量为258.9 m Ah/g（2.0~4.8 V）,首次充放电效率为75.6%;在1C充放电时,首次放电比容量为204.6 m Ah/g,循环10次后放电比容量为179.9 m Ah/g;2C倍率下仍保持了141.4 m Ah/g的放电比容量。
文摘富锂材料Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54-x)Zr_xO_2(x=0,0.02,0.05,0.1)是采用高温固相法合成,研究中采用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外吸收光谱(FTIR)及电化学方法等手段进行了表征。实验结果表明,随着Zr含量增加,材料的晶胞参数发生较大变化,Zr的掺杂抑制了Li1.2Ni0.13Co0.13Mn0.54O2高温合成时Mn3+的产生,有利于锂离子的可逆脱嵌,所合成富锂材料的粒径分布均匀,结晶性较佳。此外,电特性测试结果表明,Li1.2Ni0.13Co0.13Mn0.49Zr0.05O2富锂材料具有较佳的电性能,0.1 C下放电比容量达366 m Ah/g,循环100次后放电比容量保持率为96%。
基金financially supported by the National Natural Science Foundation of China(No.52374301)the Natural Science Foundation of Hebei Province(No.E2022501014)+2 种基金the Science and Technology Research Youth Fund Project of Higher Education Institutions of Hebei Province(No.QN2022196)the Fundamental Research Funds for the Central Universities(No.N2123001)the Natural Science Foundation of Hebei Province of China(No.B2020501003)。
文摘Due to the low cost,high working voltage and high storage capacity,Li-rich Mn-based layered compounds show promise as the cathode materials for lithiumion batteries(LIBs).However,the side reactions at the solid-liquid interface of the cathode will lead to rapid capacity decay and inferior rate performance.Herein,this article proposes a liquid-phase dispersion strategy to introduce a Na_(2)WO_(4)layer on the Li_(1.2)Ni_(0.13)-Co_(0.13)Mn_(0.54)O_(2) cathode,which can reduce the side effects between raw materials and electrolyte and promote the insertion/extraction rate of Li^(+),thus enhancing the material stability and rate performance.As a result,the capacity retention rate is 96.9%after 200 cycles under 2C.Moreover,the capacities are 177.5,149.5,111.1 and58.3 mAh·g^(-1)at 1C,2C,5C and 10C,implying a superior fast charging performance.The exceptional performance can be ascribed to both the increased conductivity and enhanced structural stability of the cathode material.What's more,based on the investigation of ion insertion/extraction behavior in electrode materials and the ion migration kinetics in the electrolyte,this study suggests that coating Li-rich Mn-based materials with Na_(2)WO_(4)can be a promising strategy to improve their performance in LIBs.
基金Project(51772333) supported by the National Natural Science Foundation of China。
文摘Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle performance and poor rate property hinder its large-scale application.The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate.In this study,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2) is modified by using Li_(1.4)Al_(0.4)Ti_(1.6)(PO_(4))_(3)(LATP)ionic conductor.The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C,with a capacity retention of 81%.Compared with the uncoated pristine LRNCM(188.4 m A·h/g and 76%),LRNCM after the LATP modification shows superior cycle performance.Moreover,the lithium-ion diffusion coefficient D_(Li+)is a crucial factor affecting the rate performance,and the D_(Li+)of the LRNCM material is improved from 4.94×10^(-13) to 5.68×10^(-12)cm^(2)/s after modification.The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C,with an improved rate performance.Thus,the modification layer can considerably enhance the electrochemical performance of LRNCM.
