The synthesis atmosphere plays a fundamental role in determining the physicochemical properties and electrochemical performance of NMC811 cathode materials used in lithium-ion batteries. This study investigates the effect of carbonate impurities generated during synthesis by comparing three distinct samples: NMC811 calcined in ambient air, NMC811 calcined in synthetic air to mitigate carbonate formation, and NMC811 initially calcined in ambient air followed by annealing in synthetic air to eliminate carbonate species. Physicochemical characterization through XRD, SEM, FTIR, and TGA techniques revealed noticeable differences in the structural and chemical properties among the samples. Electrochemical assessments conducted via coin-cell testing demonstrate superior performance for materials synthesized in synthetic air, exhibiting an enhanced discharge capacity of 145.4 ± 4.8 mA h g⁻¹ compared to materials synthesized in normal air (109.4 ± 4.3 mA h g⁻¹) at C/10. More importantly, sample annealing in synthetic air after air calcination partially recovers the electrochemical performance of the cathode (142.1 ± 4.6 mA h g⁻¹ at C/10) and this is related to the elimination of carbonate species from the ceramic powder. These findings highlight the importance of controlling synthesis conditions, particularly the atmosphere, to tailor the properties of NMC811 cathode materials for optimal lithium-ion battery performance.

中文翻译：

---

揭示煅烧过程中 CO2 暴露对 LiNi0.8Co0.1Mn0.1O2 理化和电化学性质的影响


合成气氛在决定锂离子电池中使用的 NMC811 正极材料的物理化学性质和电化学性能方面起着重要作用。本研究通过比较三种不同的样品来研究合成过程中产生的碳酸盐杂质的影响：在环境空气中煅烧的 NMC811，在合成空气中煅烧以减少碳酸盐形成的 NMC811，以及最初在环境空气中煅烧，然后在合成空气中退火以消除碳酸盐种类的 NMC811。通过 XRD、SEM、FTIR 和 TGA 技术进行的物理化学表征揭示了样品之间的结构和化学性质存在显著差异。通过纽扣电池测试进行的电化学评估表明，在合成空气中合成的材料具有优异的性能，与在正常空气中合成的材料 （109.4 ± 4.3 mA h ^g-1） 相比，在 C/10 下，放电容量提高了 145.4 ± 4.8 mA h ^g-1。更重要的是，空气煅烧后在合成空气中进行样品退火部分恢复了阴极的电化学性能（C/10 时为 142.1 ± 4.6 mA h ^g-1），这与陶瓷粉末中碳酸盐物质的消除有关。这些发现强调了控制合成条件（尤其是大气）以定制 NMC811 正极材料的性能以实现最佳锂离子电池性能的重要性。