Details

Autor(en) / Beteiligte

• Li, Zheng-Yao
• Gao, Rui
• Sun, Limei
• Hu, Zhongbo
• Liu, Xiangfeng

Titel

Designing an advanced P2-Na0.67Mn0.65Ni0.2Co0.15O2 layered cathode material for Na-ion batteries

Erscheinungsjahr

2015-01

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A high performance layered P2-Na 0.67 Mn 0.65 Ni 0.2 Co 0.15 O 2 cathode material for sodium ion batteries with high rate capability and excellent long-life cyclic performance has been successfully designed and synthesized by a simple sol-gel method. In comparison with the reported Na 0.7 MnO 2 , the designed P2-Na 0.67 Mn 0.65 Ni 0.2 Co 0.15 O 2 cathode material can be charged and discharged in an extended voltage range of 1.5-4.2 V and shows reversible capacities of 155, 144, 137, 132 and 126 mA h g −1 at different current densities of 12, 24, 48, 120 and 240 mA g −1 , respectively. Even at high current densities of 480 (2C), 1200 (5C) and 1920 mA g −1 (8C) it can still deliver capacities of 117, 93 and 70 mA h g −1 , respectively, which are much higher than those of the recently reported Na 0.5 [Ni 0.23 Fe 0.13 Mn 0.63 ]O 2 . In addition, the Na 0.67 Mn 0.65 Ni 0.2 Co 0.15 O 2 cathode material also displays an excellent capacity retention ca. 85% and 78% after 100 cycles at 0.05C and 0.5C, respectively. It is also proposed that Mn 4+ may be "activated" in a low voltage range, especially below 2.0 V, which contributes to the additional capacity. The Na-ion diffusion coefficient, D Na+ , is ca. 10 −14 cm 2 s −1 as calculated by the PITT and the discharge diffusion coefficient is a little larger than the charge one. The designed Na 0.67 Mn 0.65 Ni 0.2 Co 0.15 O 2 shows great potential as a cathode material for sodium ion batteries. An advanced P2-Na 0.67 Mn 0.65 Ni 0.2 Co 0.15 O 2 cathode material for sodium ion batteries with high rate capability and cyclability has been designed and synthesized.