As a promising cathode material of sodium-ion battery, P2-type NaNiMnO (NNMO) possesses a theoretically high capacity and working voltage to realize high energy storage density. However, it still suffers from poor cycling stability mainly incurred by the undesirable P2-O2 phase transition. Herein, the electrochemically active Fe ions are introduced into the lattice of NNMO, forming NaNiMnFe O ( x = 0, 1/24, 1/12, 1/8, 1/6) to effectively stabilize the P2-type crystalline structure. In such Fe-substituted materials, both Ni/Ni and Fe/Fe couples take part in the redox reactions, and the P2-O2 phase transition is well restrained during cycling, as verified by ex situ X-ray diffraction. As a result, the optimized NaNiMnFeO (1/12-NNMF) has a long-term cycling stability with the fading rate of 0.05% per cycle over 300 cycles at 5 C. Furthermore, the 1/12-NNMF delivers excellent rate capabilities (65 mA h g at 25 C) and superior low-temperature performance (the capacity retention of 94% at -25 °C after 80 cycles) owing to the enhanced Na diffusion upon Fe doping, which is deduced by the studies of electrode kinetics. More significantly, the 1/12-NNMF also displays remarkable sodium-ion full-cell properties when merged with an LS-Sb@G anode, thus implying the possibility of their practical application.
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http://dx.doi.org/10.1021/acsami.8b12204 | DOI Listing |
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December 2024
School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
NaNiMnO (NNM) is regarded as a promising cathode material for Na-ion batteries (NIBs), but suffers from irreversible phase transformations characterized by multiple voltage plateaus, resulting in poor cycle stability and inferior rate capability. To address these issues, the NaNiCuZnMnO (NNCZM) cathode material is synthesized by a cation chelation and reassembly process, which can promote a more uniform element distribution than that prepared by the solid-state method (S-NNCZM), resulting in better Na diffusion kinetics and rate capability. Replacing Ni with a small amount of Zn prevents the P2-O2 phase transformation, while replacing Ni with an appropriate amount of electrochemically active Cu eliminates Na-vacancy ordering and additionally contributes to capacity.
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December 2024
Department of Materials Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea.
The rapid capacity loss attributed to irreversible phase reactions and structural instability has consistently affected the development of P2-layered cathode materials. Moreover, the introduction of costly elements such as single or multiple dopants has failed to resolve the sustainability challenges in designing an optimal Mn-based layered oxide cathode. This study proposes a Co-Ni-free, poly-elemental doping strategy (Li, Mg, and Cu) combined with high sodium content for an Mn-based P2-layered cathode designed for Na ion storage.
View Article and Find Full Text PDFAdv Mater
November 2024
Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
Chemistry
December 2024
Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, People's Republic of China.
P2-type layered transition metal oxide NaNiMnO is considered as a promising cathode for advanced sodium-ion batteries due to its high theoretical specific capacity. However, the P2-type cathode suffers severe P2-O2 phase transition during cycling process, resulting unsatisfactory cyclic stability and rate capability. Herein, a Ca/Li co-doped P2-type NaCaNiMnLiO (NCNMLO) cathode material was synthesized through a simple sol-gel method.
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December 2024
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P.R. China.
Layered transition metal oxides are widely considered as ideal cathode materials for SIBs. However, the existing P2 and O3 structures possess specific issues, which limit their practical applications. To address these issues, this work designed a novel intergrowth layered oxide cathode with P2 and O3 phases by implementing Cu and Ti into the structure with the formation of high-entropy cathode materials with superior performance for SIBs.
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