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
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.
