소듐 이온 배터리에서 우수한 속도 용량과 장기 사이클링 안정성을 지닌 수소 처리된 소듐크롬옥사이드 양극재에 미치는 영향에 대한 연구 = Study on Effect of Hydrogen Treatment on NaCrO2 Cathode for a superior rate capability and long-cycling stability of sodium ion battery

다국어 초록 (Multilingual Abstract)

Layered NaCrO₂ is considered a promising cathode material for sodium-ion batteries (SIBs) due to its high theoretical capacity and structural simplicity. However, its practical application is hindered by capacity fading and poor rate performance, primarily caused by sluggish Na⁺ kinetics, phase transitions, and interfacial deterioration during prolonged cycling. In this study, we systematically investigated the effect of varying H₂/Ar atmospheric heat treatments during the synthesis of NaCrO₂. Structural and surface analyses using XRD, SEM, TEM, Raman, and XPS revealed that hydrogenation induced beneficial oxygen vacancies without altering the particle morphology. Electrochemical studies demonstrated that the NCO-25 sample achieved the highest reversible capacity of 106 mAh g⁻¹ at 2 C after 300 cycles, significantly outperforming the bare NCO sample (52 mAh g⁻¹). This superior performance is attributed to the abundant oxygen vacancies, which facilitated rapid electron/ion transport and enhanced structural stability. Quantitative analysis revealed that both diffusion-controlled and capacitive-controlled processes contributed to the electrochemical sodium storage behavior of the electrode. Furthermore, the NCO-25//HC full cell exhibited excellent cycling stability, retaining 86.3% of its initial capacity after 300 cycles. This study offers new insights into synthetic reduction engineering for Na-based cathodes and provides a promising pathway for optimizing the performance of NaCrO₂ and related layered oxide materials in sodium-ion batteries.

목차 (Table of Contents)

• Abstract. 2
• List of Figures. 4
• 1. Introduction. 6
• 2 Experimental Section. 9
• 2.1. Material characterizations. 9
• 2.2. Cell assembly. 9
• 2.3. Electrochemical measurements. 10
• 3. Results and Discussion. 11
• 3.1. Morphology and Characterization . 11
• 3.2. Electrochemical analysis. 18
• 3.3. Mechanism. 32
• 4. Conclusions. 33
• 5. References. 34