橄榄石结构的LiFePO_(4)正极材料因其多重优势被广泛应用于新能源汽车和储能领域,但其较差的电导率和缓慢的锂离子扩散速率限制了其低温和倍率等性能。元素掺杂被认为是一种改善正极材料倍率、低温等性能的有效策略。采用固相法合成了...橄榄石结构的LiFePO_(4)正极材料因其多重优势被广泛应用于新能源汽车和储能领域,但其较差的电导率和缓慢的锂离子扩散速率限制了其低温和倍率等性能。元素掺杂被认为是一种改善正极材料倍率、低温等性能的有效策略。采用固相法合成了稀土金属铕掺杂的Li Fe_(1-x)Eu_(x)PO_(4)/C正极材料,并研究了铕掺杂量对Li Fe PO_(4)形貌、结构和电化学性能的影响。结果表明,铕掺杂能够改善Li Fe PO_(4)/C的电化学性能,其中Li Fe_(0.97)Eu_(0.03)PO_(4)/C表现出最佳的倍率、低温和循环性能,其组成的纽扣电池在20C高倍率下放电比容量为95.1 m A·h/g(较Li Fe PO_(4)/C提升57.7%),在低温(-20℃、0.1C)下的放电比容量为81.5 m A·h/g(较Li Fe PO_(4)/C提升73.8%),1C下经200次循环后其容量保持率为96.43%(较Li Fe PO_(4)/C高出2.46%)。X射线衍射分析和扫描电镜分析结果表明,铕的掺入能增大Li Fe PO_(4)的晶胞体积,降低Li和O原子之间的结合能,从而提高锂离子的扩散速率。电化学交流阻抗测试结果表明,Li Fe_(0.97)Eu_(0.03)PO_(4)/C表现出最低的电荷转移电阻和最高的锂离子扩散系数,其锂离子扩散系数比未掺杂的Li Fe PO_(4)/C高出2个数量级,这解释了其出色的倍率、低温和循环性能。展开更多
A green environmental protection and enhanced leaching process was proposed to recover all elements from spent lithium iron phosphate(LiFePO_(4)) lithium batteries.In order to reduce the influence of Al impurity in th...A green environmental protection and enhanced leaching process was proposed to recover all elements from spent lithium iron phosphate(LiFePO_(4)) lithium batteries.In order to reduce the influence of Al impurity in the recovery process,NaOH was used to remove impurity.After impurity removal,the spent LiFePO_(4) cathode material was used as raw material under the H_(2)SO_(4) system,and the pressure oxidation leaching process was adopted to achieve the preferential leaching of lithium.The E-pH diagram of the Fe-P-Al-H_(2)O system can determine the stable region of each element in the recovery process of spent LiFePO_(4)Li-batteries.Under the optimal conditions(500 r·min^(-1),15 h,363.15 K,0.4 MPa,the liquid-solid ratio was 4:1 ml·g^(-1)and the acid-material ratio was 0.29),the leaching rate of Li was 99.24%,Fe,Al,and Ti were 0.10%,2.07%,and 0.03%,respectively.The Fe and P were precipitated and recovered as FePO_(4)·2H_(2)O.The kinetic analysis shows that the process of high-pressure acid leaching of spent LiFePO_(4) materials depends on the surface chemical reaction.Through the life cycle assessment(LCA)of the spent LiFePO_(4) whole recovery process,eight midpoint impact categories were selected to assess the impact of recovery process.The results can provide basic environmental information on production process for recycling industry.展开更多
在水热法合成LiFePO_(4)和HF刻蚀合成Mxene(金属碳/氮化物)的基础上,通过湿化学法制备了不同Mxene含量的Mxene/LiFePO_(4)复合正极材料,并对其物相、形貌和电化学性能进行了研究。结果表明,Mxene纳米片在LFP颗粒中的负载,使得LiFePO_(4)...在水热法合成LiFePO_(4)和HF刻蚀合成Mxene(金属碳/氮化物)的基础上,通过湿化学法制备了不同Mxene含量的Mxene/LiFePO_(4)复合正极材料,并对其物相、形貌和电化学性能进行了研究。结果表明,Mxene纳米片在LFP颗粒中的负载,使得LiFePO_(4)和Mxene之间通过“点到面”的导电模式在复合电极中构建高效导电网络,提高LiFePO_(4)正极材料的电子导电性。同时,Mxene二维层状结构的特点缩短了锂离子在正极材料中的扩散路径。因此,Mxene/LiFePO_(4)正极材料表现出良好的电化学性能,包括离子导电性和电子导电性等。其中,3%Mxene的负载,在0.1、1和5C充放电倍率下,首次放电比容量分别为159.3、136.8和100.2 m Ah·g^(-1),表现出良好的循环稳定性。展开更多
以Li H2PO4、Fe2O3及葡萄糖为原材料,采用高温高能球磨法(HTHEBM)制备了性能优良的碳包覆磷酸铁锂(Li Fe PO4/C)正极材料。在该法中,高能球磨将机械能转变为热能,有效降低了烧结温度且减少了烧结时间,在600℃下9 h烧结后获得纯相的Li Fe...以Li H2PO4、Fe2O3及葡萄糖为原材料,采用高温高能球磨法(HTHEBM)制备了性能优良的碳包覆磷酸铁锂(Li Fe PO4/C)正极材料。在该法中,高能球磨将机械能转变为热能,有效降低了烧结温度且减少了烧结时间,在600℃下9 h烧结后获得纯相的Li Fe PO4/C正极材料。利用X射线衍射、扫描电镜、透射电镜、电化学性能测试等方法研究产物的结构、形貌及电化学性能。结果表明:所得Li Fe PO4/C材料为类球型橄榄石型结构,平均粒径为0.5μm;在0.1 C充放电倍率下,首次放电比容量为152.5 mAh·g-1;不同充放电倍率下,60次循环后放电比容量基本不变。与传统高温固相法及高温球磨法在相同条件下所制备的磷酸铁锂正极材料相比,本方法所得Li Fe PO4/C材料的性能明显较优。展开更多
Cathode material LiFePO4 of lithium-ion battery was synthesized by microwave heating. The "carbon-included" LiFePO4 with improved conductivity was synthesized by the addition of graphite. And the influence o...Cathode material LiFePO4 of lithium-ion battery was synthesized by microwave heating. The "carbon-included" LiFePO4 with improved conductivity was synthesized by the addition of graphite. And the influence of microwave-heating time on structure, morphology and charge/discharge performance of the products was discussed. The results of XRD, SEM, XPS, CV and charge/discharge testing measurements showed that the LiFePO4 product after 9 min in microwave oven had more advantages than other products.展开更多
文摘橄榄石结构的LiFePO_(4)正极材料因其多重优势被广泛应用于新能源汽车和储能领域,但其较差的电导率和缓慢的锂离子扩散速率限制了其低温和倍率等性能。元素掺杂被认为是一种改善正极材料倍率、低温等性能的有效策略。采用固相法合成了稀土金属铕掺杂的Li Fe_(1-x)Eu_(x)PO_(4)/C正极材料,并研究了铕掺杂量对Li Fe PO_(4)形貌、结构和电化学性能的影响。结果表明,铕掺杂能够改善Li Fe PO_(4)/C的电化学性能,其中Li Fe_(0.97)Eu_(0.03)PO_(4)/C表现出最佳的倍率、低温和循环性能,其组成的纽扣电池在20C高倍率下放电比容量为95.1 m A·h/g(较Li Fe PO_(4)/C提升57.7%),在低温(-20℃、0.1C)下的放电比容量为81.5 m A·h/g(较Li Fe PO_(4)/C提升73.8%),1C下经200次循环后其容量保持率为96.43%(较Li Fe PO_(4)/C高出2.46%)。X射线衍射分析和扫描电镜分析结果表明,铕的掺入能增大Li Fe PO_(4)的晶胞体积,降低Li和O原子之间的结合能,从而提高锂离子的扩散速率。电化学交流阻抗测试结果表明,Li Fe_(0.97)Eu_(0.03)PO_(4)/C表现出最低的电荷转移电阻和最高的锂离子扩散系数,其锂离子扩散系数比未掺杂的Li Fe PO_(4)/C高出2个数量级,这解释了其出色的倍率、低温和循环性能。
基金supported by the National Natural Science Foundation of China(51834008,52022109,52274307,and 21804319)National Key Research and Development Program of China(2021YFC2901100)+1 种基金Science Foundation of China University of Petroleum,Beijing(2462022QZDX008,2462021QNX2010,2462020YXZZ019 and 2462020YXZZ016)State Key Laboratory of Heavy Oil Processing(HON-KFKT2022-10).
文摘A green environmental protection and enhanced leaching process was proposed to recover all elements from spent lithium iron phosphate(LiFePO_(4)) lithium batteries.In order to reduce the influence of Al impurity in the recovery process,NaOH was used to remove impurity.After impurity removal,the spent LiFePO_(4) cathode material was used as raw material under the H_(2)SO_(4) system,and the pressure oxidation leaching process was adopted to achieve the preferential leaching of lithium.The E-pH diagram of the Fe-P-Al-H_(2)O system can determine the stable region of each element in the recovery process of spent LiFePO_(4)Li-batteries.Under the optimal conditions(500 r·min^(-1),15 h,363.15 K,0.4 MPa,the liquid-solid ratio was 4:1 ml·g^(-1)and the acid-material ratio was 0.29),the leaching rate of Li was 99.24%,Fe,Al,and Ti were 0.10%,2.07%,and 0.03%,respectively.The Fe and P were precipitated and recovered as FePO_(4)·2H_(2)O.The kinetic analysis shows that the process of high-pressure acid leaching of spent LiFePO_(4) materials depends on the surface chemical reaction.Through the life cycle assessment(LCA)of the spent LiFePO_(4) whole recovery process,eight midpoint impact categories were selected to assess the impact of recovery process.The results can provide basic environmental information on production process for recycling industry.
文摘在水热法合成LiFePO_(4)和HF刻蚀合成Mxene(金属碳/氮化物)的基础上,通过湿化学法制备了不同Mxene含量的Mxene/LiFePO_(4)复合正极材料,并对其物相、形貌和电化学性能进行了研究。结果表明,Mxene纳米片在LFP颗粒中的负载,使得LiFePO_(4)和Mxene之间通过“点到面”的导电模式在复合电极中构建高效导电网络,提高LiFePO_(4)正极材料的电子导电性。同时,Mxene二维层状结构的特点缩短了锂离子在正极材料中的扩散路径。因此,Mxene/LiFePO_(4)正极材料表现出良好的电化学性能,包括离子导电性和电子导电性等。其中,3%Mxene的负载,在0.1、1和5C充放电倍率下,首次放电比容量分别为159.3、136.8和100.2 m Ah·g^(-1),表现出良好的循环稳定性。
文摘以Li H2PO4、Fe2O3及葡萄糖为原材料,采用高温高能球磨法(HTHEBM)制备了性能优良的碳包覆磷酸铁锂(Li Fe PO4/C)正极材料。在该法中,高能球磨将机械能转变为热能,有效降低了烧结温度且减少了烧结时间,在600℃下9 h烧结后获得纯相的Li Fe PO4/C正极材料。利用X射线衍射、扫描电镜、透射电镜、电化学性能测试等方法研究产物的结构、形貌及电化学性能。结果表明:所得Li Fe PO4/C材料为类球型橄榄石型结构,平均粒径为0.5μm;在0.1 C充放电倍率下,首次放电比容量为152.5 mAh·g-1;不同充放电倍率下,60次循环后放电比容量基本不变。与传统高温固相法及高温球磨法在相同条件下所制备的磷酸铁锂正极材料相比,本方法所得Li Fe PO4/C材料的性能明显较优。
文摘Cathode material LiFePO4 of lithium-ion battery was synthesized by microwave heating. The "carbon-included" LiFePO4 with improved conductivity was synthesized by the addition of graphite. And the influence of microwave-heating time on structure, morphology and charge/discharge performance of the products was discussed. The results of XRD, SEM, XPS, CV and charge/discharge testing measurements showed that the LiFePO4 product after 9 min in microwave oven had more advantages than other products.
