Synthesis of Vanadium Nitride-Hard Carbon Composites from Cellulose and Their Performance for Sodium-Ion Batteries
Synthesis of Vanadium Nitride-Hard Carbon Composites from Cellulose and Their Performance for Sodium-Ion Batteries
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DOI：
10.1021/acsaem.0c00003
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发表时间：
2020-05-26
影响因子：
6.4
通讯作者：
Hector, Andrew L.
中科院分区：
文献类型：
--
作者：
Cheng, Hang;Garcia-Araez, Nuria;Hector, Andrew L.
通过在高性能硬碳上受控形成薄且均匀分散的氮化钒（VN）纳米颗粒层，开发出了一种有前途的钠离子电池阳极材料。硬碳是钠离子负极的标准（预）商业材料，我们的硬碳电极表现出与最先进技术相当的电化学性能。VN的引入提高了容量：添加8.6wt%VN，硬碳基电极实现第一循环可逆（氧化，去辐射）容量在50 mA g（-1）下为354 mA h g（-1），而使用纯硬碳时为302 mA h g（-1）。与纯硬碳相比，当仅涉及VN的质量时，在添加VN时实现的额外比容量为605 mA h g（-1），这是迄今报道的钠离子电池中VN材料的最高容量。此外，VN还提高了循环的容量保持率：在50次循环后，具有8.6重量% VN的硬碳电极的可逆容量为294 mA h g（-1），而纯硬碳为239 mA h g（-1）。这种有前途的新材料是通过一种新的、易于扩展的合成方法获得的，在该方法中，棉絮与钒源（VOCl 3）反应，然后在N-2中进行单一焙烧步骤。洞察到的反应机理是通过非原位表征的放电和充电电极。
A promising material for sodium-ion battery anodes has been developed through the controlled formation of a thin, uniformly dispersed layer of vanadium nitride (VN) nanoparticles onto a high-performance hard carbon. Hard carbon is the standard (pre)commercial material for sodium-ion negative electrodes, and our hard carbon electrodes exhibit an electrochemical performance comparable to the state-of-the-art. The introduction of VN produces an increased capacity: with addition of 8.6 wt % VN, the hard carbon-based electrode achieves a first cycle reversible (oxidation, desodiation) capacity of 354 mA h g(-1) at 50 mA g(-1), while with pure hard carbon it is 302 mA h g(-1). The additional specific capacity achieved upon addition of VN, compared with the pure hard carbon, is 605 mA h g(-1) when referred to the mass of VN only, which is the highest capacity of VN materials in sodium-ion batteries reported to date. In addition, VN also improves the capacity retention with cycling: after 50 cycles the reversible capacity of hard carbon electrodes with 8.6 wt % VN is 294 mA h g(-1), while with pure hard carbon it is 239 mA h g(-1). This promising new material is obtained via a new and easily scalable synthesis method in which cotton wool is reacted with a vanadium source (VOCl3), followed by a single firing step in N-2. Insights into the reaction mechanism are obtained by ex situ characterization of the discharged and charged electrodes.