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
Li-rich manganese-based materials are considered to be the mainstream cathode materials for next-generation lithium-ion batteries due to high discharge capacity and low cost,but poor cycle life and high temperature pe...Li-rich manganese-based materials are considered to be the mainstream cathode materials for next-generation lithium-ion batteries due to high discharge capacity and low cost,but poor cycle life and high temperature performance limit their development.Herein,LiZr_(2)(PO_(4))_(3)(LZPO)is coated on the surface of spherical Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)(LMNCO)material by a simple wet chemical method.The LZPO layer not only has the function of traditional coating layer to inhibit the occurrence of side reactions between electrolyte and LMNCO surface but also promotes the formation of spinel phase in the layered structure,increases the content of lattice oxygen,and reduces the content of absorbed oxygen.Thus,LZPO coated LMNCO has a more stable layered structure during cycling compared pure LMNCO,which improves effectively its long life and high temperature performance.The capacity loss rate of LZPO coated LMNCO is only 16.2%and 11.9%after 350 cycles at 25℃and 200 cycles at 50℃,respectively.Moreover,the capacity retention rate of the full cell composed of LZPO coated LMNCO and graphite is 70.7%after 200 cycles at 1.0 C.The coating layer toward stable surface structure can provide an idea for the modification of cathode materials,especially for Li-rich manganese-based materials.展开更多
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.
基金support from the Key Project of Science and Technology Research of Chongqing Education Commission of China(No.KJZDK201801103)the Venture&Innovation Support Program for Chongqing Overseas Returnees(No.cx2019128)Scientific Research Foundation of Chongqing University of Technology(No.2022ZDZ004).
文摘Li-rich manganese-based materials are considered to be the mainstream cathode materials for next-generation lithium-ion batteries due to high discharge capacity and low cost,but poor cycle life and high temperature performance limit their development.Herein,LiZr_(2)(PO_(4))_(3)(LZPO)is coated on the surface of spherical Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)(LMNCO)material by a simple wet chemical method.The LZPO layer not only has the function of traditional coating layer to inhibit the occurrence of side reactions between electrolyte and LMNCO surface but also promotes the formation of spinel phase in the layered structure,increases the content of lattice oxygen,and reduces the content of absorbed oxygen.Thus,LZPO coated LMNCO has a more stable layered structure during cycling compared pure LMNCO,which improves effectively its long life and high temperature performance.The capacity loss rate of LZPO coated LMNCO is only 16.2%and 11.9%after 350 cycles at 25℃and 200 cycles at 50℃,respectively.Moreover,the capacity retention rate of the full cell composed of LZPO coated LMNCO and graphite is 70.7%after 200 cycles at 1.0 C.The coating layer toward stable surface structure can provide an idea for the modification of cathode materials,especially for Li-rich manganese-based materials.
