碳包覆和掺杂碘的 LiFeBO3 作为锂离子电池正极材料的电化学和光谱研究,Bulletin of the Korean Chemical Society

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碳包覆和掺杂碘的 LiFeBO3 作为锂离子电池正极材料的电化学和光谱研究
Bulletin of the Korean Chemical Society ( IF 2.3 ) Pub Date : 2022-12-23 , DOI: 10.1002/bkcs.12663
Yujin Jeong ₁ , Rajeev Kumar ₂ , Youngil Lee _{1,

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Affiliation

在这项研究中，单斜晶系 LiFeBO ₃被碳包覆并通过固态反应掺杂碘，以提高原始 LiFeBO ₃作为锂离子电池阴极材料的电化学性能。为了提高LiFeBO ₃的导电性，在硼酸盐的氧位点掺杂有限量（x = 0.005）的高电负性碘阴离子，生成LiFeBO _{3− x} I _{2 x}。_{然后在 LiFeBO 2.995} I _0.01上原位沉积薄碳层颗粒（以产生“LFBI/C”）以保护它们免受空气和湿气的影响。场发射扫描电子显微镜 (FE-SEM) 数据表明合成样品的聚集形态。粉末 X 射线衍射 (XRD) 和⁷ Li 魔角自旋 (MAS) 核磁共振 (NMR) 测量表明，掺杂和未掺杂的基于 LiFeBO ₃的样品均主要具有单斜晶结构，尽管有少量的钒长石型相是在碘掺杂时形成的。X射线光电子能谱（XPS）和能量色散X射线能谱（EDX）数据证实了碘在阴极材料中的成功嵌入。LFBI/C 在 0.05 C 倍率下的比放电容量 (144.68 mAh g ^-1 ) 高于碳包覆的 LiFeBO₃ (122.46 毫安时克^-1 )。LFBI/C 的容量增加在以 1 C 倍率进行的长充放电循环和整体倍率性能中也很明显。有趣的是，即使在 10 C 倍率下，碘掺杂样品也表现出非常高的比放电容量。

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Electrochemical and spectroscopic studies on carbon-coated and iodine-doped LiFeBO3 as a cathode material for lithium-ion batteries

In this study, monoclinic LiFeBO₃ was carbon-coated and iodine doped via a solid-state reaction to improve the electrochemical performance of pristine LiFeBO₃ as cathode material in lithium-ion batteries. In order to enhance the electrical conductivity of LiFeBO₃, the highly electronegative iodide anion was doped in a limited amount (x = 0.005) at the oxygen site of the borate to produce LiFeBO_3−xI_2x. A thin carbon layer was then deposited in situ on the LiFeBO_2.995I_0.01 particles (to produce “LFBI/C”) to protect them from air and moisture. Field-emission scanning electron microscopy (FE-SEM) data indicated the aggregated morphology of the synthesized samples. Powder X-ray diffraction (XRD) and ⁷Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) measurements revealed that both the doped and undoped LiFeBO₃-based samples had mainly monoclinic structures, although a small amount of a vonsenite-type phase was formed upon iodine doping. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) data confirmed the successful insertion of iodine in the cathode material. The specific discharge capacity of LFBI/C at 0.05 C rate (144.68 mAh g⁻¹) was higher than that of carbon-coated LiFeBO₃ (122.46 mAh g⁻¹). The increased capacity of LFBI/C was also evident in long charge–discharge cycles conducted at 1 C rate and in the overall rate performance. Interestingly, the iodine-doped sample exhibited significantly high specific discharge capacity even at 10 C rate.

更新日期：2022-12-23

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