Micron School of Materials Science and Engineering, Boise State University, Boise, ID 83725, USA.
Nanoscale. 2017 Aug 3;9(30):10757-10763. doi: 10.1039/c7nr03017g.
We report an amorphous boron nanorod anode material for lithium-ion batteries prepared through smelting non-toxic boron oxide in liquid lithium. Boron in theory can provide capacity as high as 3099 mA h g by alloying with Li to form BLi. However, experimental studies of the boron anode have been rarely reported for room temperature lithium-ion batteries. Among the reported studies the electrochemical activity and cycling performance of the bulk crystalline boron anode material are poor at room temperature. In this work, we utilized an amorphous nanostructured one-dimensional (1D) boron material aiming at improving the electrochemical reactivity between boron and lithium ions at room temperature. The amorphous boron nanorod anode exhibited, at room temperature, a reversible capacity of 170 mA h g at a current rate of 10 mA g between 0.01 and 2 V. The anode also demonstrated good rate capability and cycling stability. The lithium storage mechanism was investigated by both sweep voltammetry measurements and galvanostatic intermittent titration techniques (GITTs). The sweep voltammetric analysis suggested that the contributions from lithium ion diffusion into boron and the capacitive process to the overall lithium charge storage are 57% and 43%, respectively. The results from GITT indicated that the discharge capacity at higher potentials (>∼0.2 V vs. Li/Li) could be ascribed to a capacitive process and at lower potentials (<∼0.2 V vs. Li/Li) to diffusion-controlled alloying reactions. Solid state nuclear magnetic resonance (NMR) measurement further confirmed that the capacity is from electrochemical reactions between lithium ions and the amorphous boron nanorod. This work provides new insights into designing nanostructured boron materials for lithium-ion batteries.
我们报告了一种通过在液态锂中熔炼无毒氧化硼制备的用于锂离子电池的无定形硼纳米棒阳极材料。理论上，硼通过与 Li 形成 BLi 可以提供高达 3099 mA h g 的容量。然而，室温锂离子电池的硼阳极实验研究很少有报道。在报道的研究中，块状晶体硼阳极材料的电化学活性和循环性能在室温下较差。在这项工作中，我们利用了一种无定形的纳米结构一维（1D）硼材料，旨在提高硼和锂离子在室温下的电化学反应性。无定形硼纳米棒阳极在室温下以 10 mA g 的电流速率在 0.01 至 2 V 之间表现出 170 mA h g 的可逆容量。该阳极还表现出良好的倍率性能和循环稳定性。通过循环伏安法测量和恒电流间歇滴定技术（GITT）研究了锂存储机制。扫面伏安分析表明，锂离子扩散进入硼和电容过程对整体锂电荷存储的贡献分别为 57%和 43%。GITT 的结果表明，较高电位（>∼0.2 V vs. Li/Li）下的放电容量可能归因于电容过程，而较低电位（<∼0.2 V vs. Li/Li）下的放电容量归因于扩散控制的合金化反应。固态核磁共振（NMR）测量进一步证实，容量来自于锂离子与无定形硼纳米棒之间的电化学反应。这项工作为设计用于锂离子电池的纳米结构硼材料提供了新的思路。
