Investigation on the structure and electrochemical performance of LiNi_0.8Co_0.1Mn_0.1O₂ modified with Sn

Ni-rich layered cathode materials are promising cathode materials for lithium-ion batteries with high energy density. To reveal the influence of Sn-coating and doping on the structure and electrochemical performances of Ni-rich layered cathode materials, LiNi_0.8Co_0.1Mn_0.1O₂, LiNi_0.8Co_0.1Mn_0.1O₂@xLi₂SnO₃ and LiNi_0.8−xCo_0.1Mn_0.1Sn_xO₂ (x = 0.02 and 0.04) are designed and synthesized. The effect of lithium-tin-oxide coating and Sn-doping on the structural and electrochemical behavior of Ni-rich cathode material are compared and investigated. Compared with the bare LiNi_0.8Co_0.1Mn_0.1O₂ cathode material, both LiNi_0.8Co_0.1Mn_0.1O₂@xLi₂SnO₃ and Sn-doped LiNi_0.8−xCo_0.1Mn_0.1Sn_xO₂ (x = 0.02 and 0.04) samples exhibit better electrochemical performances. The capacity retention for Li₂SnO₃-coated and Sn-doped materials after 270 cycles at 0.5C can reach as high as 93.7 and 96.6%, respectively. Besides, improved rate capabilities and thermal stability are also obtained for Li₂SnO₃-coated and Sn-doped materials. The superior electrochemical performances and enhanced thermal stability of Li₂SnO₃ coated samples are mainly ascribed to the higher interfacial stability and those of Sn-doped materials may be mainly due to higher structural stability and lower polarization than those of the bare LiNi_0.8Co_0.1Mn_0.1O₂ cathode material. These results indicate that the introduction of Sn ions, especially Sn doping, may be an effective strategy to improve the performance of Ni-rich layered cathode materials.