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Improved electrochemical performance of P2-type concentration-gradient cathode material Na0.65Ni0.16Co0.14Mn0.7O2 with Mn-rich core for sodium-ion batteries.

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Title: Improved electrochemical performance of P2-type concentration-gradient cathode material Na0.65Ni0.16Co0.14Mn0.7O2 with Mn-rich core for sodium-ion batteries.
Authors: Gao, Nengshuang1 (AUTHOR), Guo, Yiwen1 (AUTHOR), Chen, Yuanhua1,2,3 (AUTHOR) cyh@guat.edu.cn, Feng, shuaiqiang4 (AUTHOR), Li, Hechen1 (AUTHOR), Sun, Ruicong1 (AUTHOR), Huang, Bin1 (AUTHOR), Zhong, Shengkui3 (AUTHOR), Chen, Quanqi1,3 (AUTHOR) hpcqq@163.com
Source: Journal of Alloys & Compounds. Oct2023, Vol. 958, pN.PAG-N.PAG. 1p.
Subjects: Electrochemical electrodes, Sodium ions, Cathodes, Oxide electrodes, X-ray diffraction, Diffusion coefficients, Storage batteries
Abstract: The full concentration-gradient Na 0.65 Ni 0.16 Co 0.14 Mn 0.7 O 2 (CG-NCM), in which the composition varies gradiently from core Na 0.65 Ni 0.01 Co 0.01 Mn 0.98 O 2 to shell Na 0.65 Ni 0.31 Co 0.27 Mn 0.42 O 2 , was prepared by a co-precipitation method plus high-temperature calcination, and was investigated by XRD, SEM, TEM and electrochemical measurements. Benefiting from the special concentration-gradient core-shell structure, CG-NCM possesses higher diffusion coefficients of Na+ and the consequently better rate capability and cyclability than concentration-constant Na 0.65 Ni 0.16 Co 0.14 Mn 0.7 O 2 (CC-NCM). Galvanostatically cycled at 30 mA g−1 between 1.5 and 4.1 V (vs Na+/Na), CC-NCM and CG-NCM have initial discharge capacities of 168.5 and 162.5 mA h g−1, and the capacity retentions of 11.5 % and 51.4 % after 100 cycles, respectively. CG-NCM presents high initial discharge capacities of 144.5, 138.2 and 121.8 mA h g−1 at 75, 300 and 750 mA g−1, respectively, and exhibits capacity retentions of 70.6 %, 73.2 % and 76.9 % after 100 cycles, respectively. However, CC-NCM shows initial discharge capacities of 149.5, 136.5 and 107.3 mA h g−1 at 75, 300 and 750 mA g−1, respectively, and the matching capacity retentions are as low as 49.8 %, 52.3 % and 53.9 %, respectively. The results indicate that the construction of concentration-gradient oxide electrode materials is an effective strategy for improvement of the electrochemical performance of oxides cathodes. • Concentration-gradient Ni 0.16 Co 0.14 Mn 0.7 (OH) 2 (CG-NCMH) prepared by co-precipitation. • Full concentration-gradient Na 0.65 Ni 0.16 Co 0.14 Mn 0.7 O 2 (CG-NCM) is target product. • CG-NCM was obtained by high-temperature sintering mixture of CH 3 COONa and CG-NCMH. • CG-NCM is of Na 0.65 Ni 0.01 Co 0.01 Mn 0.98 O 2 core and Na 0.65 Ni 0.31 Co 0.27 Mn 0.42 O 2 shell. • CG-NCM is superior to concentration-constant NCM in electrochemical performance. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:The full concentration-gradient Na 0.65 Ni 0.16 Co 0.14 Mn 0.7 O 2 (CG-NCM), in which the composition varies gradiently from core Na 0.65 Ni 0.01 Co 0.01 Mn 0.98 O 2 to shell Na 0.65 Ni 0.31 Co 0.27 Mn 0.42 O 2 , was prepared by a co-precipitation method plus high-temperature calcination, and was investigated by XRD, SEM, TEM and electrochemical measurements. Benefiting from the special concentration-gradient core-shell structure, CG-NCM possesses higher diffusion coefficients of Na+ and the consequently better rate capability and cyclability than concentration-constant Na 0.65 Ni 0.16 Co 0.14 Mn 0.7 O 2 (CC-NCM). Galvanostatically cycled at 30 mA g−1 between 1.5 and 4.1 V (vs Na+/Na), CC-NCM and CG-NCM have initial discharge capacities of 168.5 and 162.5 mA h g−1, and the capacity retentions of 11.5 % and 51.4 % after 100 cycles, respectively. CG-NCM presents high initial discharge capacities of 144.5, 138.2 and 121.8 mA h g−1 at 75, 300 and 750 mA g−1, respectively, and exhibits capacity retentions of 70.6 %, 73.2 % and 76.9 % after 100 cycles, respectively. However, CC-NCM shows initial discharge capacities of 149.5, 136.5 and 107.3 mA h g−1 at 75, 300 and 750 mA g−1, respectively, and the matching capacity retentions are as low as 49.8 %, 52.3 % and 53.9 %, respectively. The results indicate that the construction of concentration-gradient oxide electrode materials is an effective strategy for improvement of the electrochemical performance of oxides cathodes. • Concentration-gradient Ni 0.16 Co 0.14 Mn 0.7 (OH) 2 (CG-NCMH) prepared by co-precipitation. • Full concentration-gradient Na 0.65 Ni 0.16 Co 0.14 Mn 0.7 O 2 (CG-NCM) is target product. • CG-NCM was obtained by high-temperature sintering mixture of CH 3 COONa and CG-NCMH. • CG-NCM is of Na 0.65 Ni 0.01 Co 0.01 Mn 0.98 O 2 core and Na 0.65 Ni 0.31 Co 0.27 Mn 0.42 O 2 shell. • CG-NCM is superior to concentration-constant NCM in electrochemical performance. [ABSTRACT FROM AUTHOR]
ISSN:09258388
DOI:10.1016/j.jallcom.2023.170386