Key Takeaways & Executive Findings
- •• Higher calcination temperatures expand Na layer spacing, enhancing Na⁺ diffusion kinetics and rate performance. • Elevated calcination temperatures reduce oxygen vacancies, improving crystallinity and cyclic stability. • Optimized NCFM delivers an initial discharge capacity of 143.3 mA·h/g at 0.1C and retains 79.28% after 100 cycles at 1C. • Calcination temperature control is a key strategy for tuning interlayer spacing and oxygen vacancies in layered oxide cathodes.
Abstract
NaCu0.2Fe0.3Mn0.5O2 (NCFM) cathode material was synthesized using a simple solid-state reaction, and the effect of calcination temperature on its interlayer spacing and oxygen vacancies concentration was investigated. Through electrochemical testing and material characterizations, higher calcination temperatures increase the electrostatic repulsion between oxygen atoms in adjacent layers, resulting in an expansion of Na layer spacing. This structural change enhances the diffusion kinetics of Na⁺, thereby significantly improving the rate performance of NCFM. Furthermore, elevated calcination temperatures facilitate the reduction of oxygen vacancies, leading to improved crystallinity. This enhancement in crystallinity mitigates structural strain during phase transitions, contributing to improved cyclic stability. Consequently, the optimized NCFM shows an initial discharge specific capacity of 143.3 mA·h/g at 0.1C, with a capacity retention rate of 79.28% after 100 cycles at 1C.
1. Introduction
Lithium-ion batteries (LIBs) have become prevalent in high-power applications for consumer electronics and electric vehicles, primarily due to their superior electrochemical performance [1−3]. However, the limited and uneven distribution of Li reserves leads to elevated costs. In contrast, sodium-ion batteries (SIBs) utilize abundant and low-cost Na resources, exhibiting chemical properties similar to those of LIBs, thereby presenting a viable alternative for large-scale energy storage applications [4,5]. Over the past decade, a variety of cathode materials have been explored for SIBs, including transition metal (TM) layered oxides, polyanionic compounds, and Prussian blue analogues. In particular, layered transition metal oxides (NaxTMO2, where TM represents Fe, Mn, Ni, Cu, Cr, etc.) are highly noticeable due to their high theoretical capacity, open framework, and facile synthesis [6−9].
Typically, NaxTMO2 compounds are generally categorized into two structural types (P2 and O3), where P and O represent prismatic and octahedral sites occupied by Na+, respectively, and the latter number refers to the stacking period of TMO2-layers in the cell unit [10−12]. The P2 phase exhibits superior cyclic stability and rate performance, attributed to the direct and rapid diffusion of Na⁺ between the trigonal prismatic Na sites. However, its low initial coulombic efficiency (ICE) has hindered its widespread practical application [13]. Conversely, O3-phase cathode, which possesses adequate Na content, provides high power density. However, it is plagued by one or more complex phase transformations that occur due to Na⁺ diffusion through the face-shared tetrahedral sites (intermediate sites) during the sodiation and desodiation processes, resulting in limited cycle stability and poor rate performance [14−17]. A common
Loading authentic research manuscript (Pages 1–5)...
Bo-wen XU, Da ZHANG, Xuan-tian FENG, Sheng-ping HOU, Peng DONG, Dong-feng XUE, Feng LIANG (2025). Effect of calcination temperature on interlayer spacing and oxygen vacancies concentration of NaCu0.2Fe0.3Mn0.5O2 layered materials for sodium-ion batteries. SinoTechIntel Verified Research. https://doi.org/10.1016/S1003-6326(25)66984-6
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the effect of calcination temperature on NaCu0.2Fe0.3Mn0.5O2 cathode material?
Higher calcination temperatures increase the interlayer spacing of Na layers and reduce oxygen vacancies, leading to improved Na⁺ diffusion kinetics and crystallinity, which enhance rate performance and cyclic stability.
How does interlayer spacing affect sodium-ion battery performance?
Expanded interlayer spacing reduces the energy barrier for Na⁺ diffusion, thereby improving rate capability and overall electrochemical performance.
What is the role of oxygen vacancies in layered oxide cathodes?
Oxygen vacancies can affect the electronic structure and structural stability. Reducing oxygen vacancies through higher calcination temperatures improves crystallinity and mitigates structural strain during phase transitions, enhancing cyclic stability.
What are the electrochemical performance metrics of the optimized NCFM material?
The optimized NCFM exhibits an initial discharge specific capacity of 143.3 mA·h/g at 0.1C and a capacity retention of 79.28% after 100 cycles at 1C.
Why is calcination temperature control important for sodium-ion battery cathodes?
Calcination temperature directly influences the crystal structure, interlayer spacing, and defect chemistry of the cathode material, which are critical for optimizing Na⁺ transport and structural stability, thus enabling high-performance sodium-ion batteries.
Related Technical Papers & Translations
A Novel Approach for Enhanced Brain Tumor Segmentation Using Multimodal MRI and Deep Learning
Brain tumor segmentation from multimodal MRI is crucial for diagnosis and treatment planning. In this study, we propose a novel deep learning framework that integrates structural and functional imaging modalities to improve segmentation accuracy. Our method employs a multi-scale attention mechanism and a hybrid loss function to handle class imbalance and boundary ambiguity. Evaluated on the BraTS benchmark, our approach achieves state-of-the-art performance, with Dice scores of 0.91, 0.87, and 0.84 for whole tumor, core, and enhancing tumor, respectively. Furthermore, we demonstrate the generalizability of our model across different scanners and protocols. Our findings suggest that the proposed method can significantly aid clinical decision-making and surgical planning.
Investigation of coupled acoustic and electrical responses and early warning approaches during re-loading of damaged coal
Initial damage from engineering disturbances in deep coal mining degrades mechanical properties and heightens dynamic-hazard risks, challenging conventional monitoring. This study probes the coupled acoustic-electrical responses of initially damaged coal under reloading and develops a multi-parameter, multi-level dynamic integrated early-warning model. Using a true-triaxial Split Hopkinson Pressure Bar (SHPB) system, we prepared specimens with graded damage by varying static deviatoric stresses and dynamic impacts. Uniaxial compression reloading was conducted with synchronous acoustic emission (AE) and resistivity monitoring. Joint time-domain responses of force, acoustics, and electricity delineated distinct loading stages. Time-frequency features were extracted via Fourier and wavelet transforms; crack architecture was quantified by 3D AE localization and fractal-dimension analysis. Initial damage markedly reduced load-bearing capacity. Resistivity decreased sharply with increasing deviatoric stress, while cumulative AE counts increased strongly. The AE spectrum evolved from bimodal to broadband with low- and high-frequency enhancement. The resistivity spectrum showed progressive bandwidth broadening, energy amplification, and high-frequency advancement. The AE spatial fractal dimension rose significantly during compaction. An integrated warning system combining multiscale entropy fusion, Temporal Convolutional Network (TCN)-Transformer forecasting, recurrence-network analysis, and a Bayesian framework yielded a 28.4 s lead time, offering a theoretical basis and technical pathway for intelligent prevention of dynamic hazards.
Influence of aggregate particle size on fracture behavior and energy evolution of cemented rockfill in the post-peak stage
Cemented rockfill (CRF) combines structural support with sustainable reuse of coal-derived solid waste. This study integrates digital image correlation, acoustic emission monitoring, and finite–discrete element simulations to investigate mechanical behavior, fracture development, and energy evolution of CRF containing 54% aggregate content with three grain-size distributions (5–10, 10–20, and 20–30 mm). Results indicate finer aggregates raise compressive strength and elastic modulus, and increase post-peak softening and residual stiffness. Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens, with cracks initiating at boundaries and propagating inward. The proportion of failed joints at comparable strains decreases markedly with finer gradation, reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations. Energy analyses reveal a coarse > medium > fine ordering in cumulative dissipation; however, finer aggregates delay rapid kinetic and dissipative energy release, promoting slower energy redistribution and improved load resistance. These findings quantify how aggregate gradation controls deformational mechanisms, crack topology, and energy partitioning, and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility, energy absorption, and structural reliability of CRF in underground engineering.