Air sensitivity of electrode materials in Li/Na ion batteries: Issues and strategies

Zhang, Ruiwang; Yang, Sijie; Li, Haobo; Zhai, Tianyou; Li, Huiqiao

doi:10.1002/inf2.12305

Cited by 71 publications

(40 citation statements)

References 121 publications

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“…S1) showed that the NNSO-E sample had the same peaks at 117, 166, and 1073 cm −1 as the Na 2 CO 3 that was also exposed to the air under the same conditions. Therefore, the impurities on the surface are possibly composed of Na 2 CO 3 •nH 2 O, NaHCO 3 •nH 2 O, NaOH, and other substances, and this finding is consistent with previous reports [23]. These impurities are residual sodium components (RSC).…”

Section: Resultssupporting

confidence: 92%

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Air degradation and rehealing of high-voltage Na0.7Ni0.35Sn0.65O2 cathode for sodium ion batteries

et al. 2022

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Layered transition metal oxides (Na x TMO 2 , TM = transition metal) are the most promising cathode candidate for sodium-ion batteries (SIBs) due to their two-dimensional ion diffusion channel that enables easy ion intercalation/ deintercalation, superior specific capacity, environmental benignity, and feasibility for mass production. Among the reported Na x TMO 2 , Na 0.7 Ni 0.35 Sn 0.65 O 2 has the highest working plateau and an average voltage as high as 3.7 V and thus has great potential as a high-energy cathode candidate for SIBs. However, its air sensitivity upon exposure and storage, which would greatly affect the cost and feasibility of its practical application, remains unclear. Here, the degradation mechanism of Na 0.7 Ni 0.35 Sn 0.65 O 2 upon air exposure was investigated by ex-situ X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that Na 0.7 Ni 0.35 Sn 0.65 O 2 suffers from severe air sensitivity and completely transforms to its hydrated phase within 4 h under 25°C and 80% relative humidity. Further, the deteriorated materials were repaired by reheating under different conditions. In-situ variable temperature XRD, infrared, Raman, and thermogravimetry analyses revealed that the recovery of the electrochemical properties and crystal structure of Na 0.7 Ni 0.35 Sn 0.65 O 2 depends on the reinsertion of sodium ions into the lattice; these sodium ions have been extracted by H 2 O upon air exposure. This work provides new insights into the air degradation of electrode materials for SIBs and a deep understanding of their reheating recovery strategy.

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Section: Resultssupporting

confidence: 92%

“…The superior cycle performance of the NNSO-E-H sample may be attributed to its clean surface. On the contrary, some RSCs, which adversely affect long-term cycle stability [23], can be found on the surface of pristine NNSO samples.…”

Section: Electrochemical Characterizationmentioning

confidence: 96%

Air degradation and rehealing of high-voltage Na0.7Ni0.35Sn0.65O2 cathode for sodium ion batteries

et al. 2022

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“…Besides natural abundances and prices of raw materials, air stability also determines the commercialization of Na x TMO 2 . ,, An air-stable electrode material should maintain its structure, chemical composition, and electrochemical properties after exposure to a specific atmosphere for a given time . However, because of the lower charge density of Na + and lower redox potential, Na x TMO 2 materials display poorer air stability than their lithium counterparts.…”

Section: Redox-active Cations and Structures For Na X Tmo2mentioning

confidence: 99%

Layered Oxide Cathodes for Sodium-Ion Batteries: Storage Mechanism, Electrochemistry, and Techno-economics

et al. 2023

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Conspectus Lithium-ion batteries (LIBs) are ubiquitous in all modern portable electronic devices such as mobile phones and laptops as well as for powering hybrid electric vehicles and other large-scale devices. Sodium-ion batteries (NIBs), which possess a similar cell configuration and working mechanism, have already been proven as ideal alternatives for large-scale energy storage systems. The advantages of NIBs are as follows. First, sodium resources are abundantly distributed in the earth’s crust. Second, high-performance NIB cathode materials can be fabricated by using solely inexpensive and noncritical transition metals such as manganese and iron, which further reduces the cost of the required raw materials. Recently, the unprecedented demand for lithium and other critical minerals has driven the cost of these primary raw materials (which are utilized in LIBs) to a historic high and thus triggered the commercialization of NIBs. Sodium layered transition metal oxides (Na x TMO2, TM = transition metal/s), such as Mn-based sodium layered oxides, represent an important family of cathode materials with the potential to reduce costs, increase energy density and cycling stability, and improve the safety of NIBs for large-scale energy storage. However, these layered oxides face several key challenges, including irreversible phase transformations during cycling, poor air stability, complex charge-compensation mechanisms, and relatively high cost of the full cell compared to LiFePO4-based LIBs. Our work has focused on the techno-economic analysis, the degradation mechanism of Na x TMO2 upon cycling and air exposure, and the development of effective strategies to improve their electrochemical performances and air stability. Correlating structure–performance relationships and establishing general design strategies of Na x TMO2 must be considered for the commercialization of NIBs. In this Account, we discuss the recent progress in the development of air-stable, electrochemically stable, and cost-effective Na x TMO2. The favorable redox-active cations for Na x TMO2 are emphasized in terms of abundance, cost, supply, and energy density. Different working mechanisms related to Na x TMO2 are summarized, including the electrochemical reversibility, the main structural transformations during the charge and discharge processes, and the charge-compensation mechanisms that accompany the (de)intercalation of Na+ ions, followed by discussions to improve the stability toward ambient air and upon cycling. Then the techno-economics are presented, with an emphasis on cathodes with different chemical compositions, cost breakdown of battery packs, and Na deficiency, factors that are critical to the large-scale implementation. Finally, this Account concludes with an overview of the remaining challenges and new opportunities concerning the practical applications of Na x TMO2, with an emphasis on the cost, large-scale fabrication capability, and electrochemical performance.

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“…[7] Obviously, only by an in-depth exploration of the mechanism of changes in the surface and near-surface layers of Ni-rich CAMs after storage in air (the main influencing component factors are H 2 O and CO 2 ), can we effectively prevent or optimize the root cause. [1,[9][10][11][12]…”

Section: Introductionmentioning

confidence: 99%

Air Instability of Ni‐Rich Layered Oxides–A Roadblock to Large Scale Application

Zhang

Yuan

Zhu

et al. 2022

Advanced Energy Materials

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Benefiting from the excellent lithium ions diffusion kinetics and considerable discharge specific capacity, Ni‐rich layered oxides have become the preferred selection cathode active materials (CAMs) for high energy density Li‐ion batteries. However, due to the distinctive electronic structure of nickel ions (Ni2+/3+/4+) and the strict criteria for sintering conditions, the Ni‐rich CAMs inherently suffer from notorious deterioration when in contact with the ambient air. This review provides a comprehensive and critical overview of air instability for Ni‐rich CAMs, a neglected but critical issue for large‐scale application. The fundamental understanding of derivation of air instability and characterizations is first given, followed by a discussion of evolution behaviors and the corresponding negative influence on fabricating properties of electrodes and electrochemical/safety performance of batteries. Afterward, various material modification strategies for improving air storage stability including pre‐treatment by doping and coating and post‐treatment by gas, wash, and heat are overviewed. Finally, some perspectives for further exploration to address the air instability issue and pave ways toward Ni‐rich CAMs’ practical applications are also proposed.

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Air sensitivity of electrode materials in Li/Na ion batteries: Issues and strategies

Cited by 71 publications

References 121 publications

Air degradation and rehealing of high-voltage Na0.7Ni0.35Sn0.65O2 cathode for sodium ion batteries

Air degradation and rehealing of high-voltage Na0.7Ni0.35Sn0.65O2 cathode for sodium ion batteries

Layered Oxide Cathodes for Sodium-Ion Batteries: Storage Mechanism, Electrochemistry, and Techno-economics

Air Instability of Ni‐Rich Layered Oxides–A Roadblock to Large Scale Application

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