经过Thomas Hornigold2018年4月12日
锂离子电池在储能中发挥着越来越重要的作用。像特斯拉这样的公司将其视为电动汽车的能源存储解决方案,并解决与可再生能源相关的间歇性问题。他们对许多电荷循环的庞大能量密度和容量使它们在移动设备中几乎无处不在 - 但它们有问题。
钠离子电池已成为最近的竞争对手。钠比锂更丰富,这些电池的安全记录更好,火灾较少。2D材亚博网站下载料具有最大的表面积与体积比,高电导率和高离子扩散率,可能会替代像石墨这样的散装材料,因为这些电池的能量浓度更高且常见。
As the field of synthesising and characterising 2D materials grows ever more advanced, these seemingly-miraculous substances are displaying fascinating and often highly useful properties. Since graphene was first synthesised through exfoliation, and new methods such as layering atoms onto a substrate with atomic layer deposition or molecular beam epitaxy have become widely used, theoreticians have been keenly exploring the potential for these materials with their calculations. Such calculations suggested in 2015 that there was the potential to synthesise a graphene-like layer of Si2BN – two atoms of silicon bound to a boron atom and a nitrogen atom.
其他石墨烯类似物(如德国烯)在晶格结构中显示屈曲,但SI2BN具有平坦的六边形结构,可以创建纳米管。预计该材料在各种不同的物理条件下都是稳定的 - 可能是80万或更高的温度。
Monolayer Si2BN was then subject to a number of theoretical characterisations, and has drawn a great deal of interest from the renewable energy industry. At first, it was considered that it might be useful as a means of hydrogen storage. Many renewables advocates hope to store the intermittent power from wind turbines and solar panels in the form of hydrogen, which can be produced by electrolysis during times when supply is at a peak.
阻止“氢经济”起飞的因素之一是储存氢的困难,这并不是特别的能量浓度和爆炸性。因此,包括美国能源部在内的研究小组的努力试图找到将氢化化学结合的材料。亚博网站下载在层表面上的硅的存在引起了希望,希望它足够反应能够储存大量氢 - 但也产生了另一种积极作用。SI20亿杆是锂离子电池的绝佳阳极。
Image credit: CyrillLutz/Shutterstock
2017年Nano Energy中的一篇论文描述了这一属性。该论文的标题是“二维SI2BN的奇怪案例:高容量电池阳极材料” - 指出了该材料的异常性质。它具有吸附和存储锂离子的理论能力,其可能比当今电池中使用的现有阳极材料大5倍。亚博网站下载已经合亚博网站下载成的2D材料通常也表现出良好的吸附性能,但是2d Si2bn与其他此类材料(例如硅烯,硼苯和2D黑色磷酸化)相吻合,以及其他材料,以及其他材料,例如石墨,二氧化钛和甲状腺钼,。
The paper’s calculations suggest that the key to this is the Si-Si-bond, as well as the unique response of the structure to adsorbing ions. As lithium/sodium ions are intercalcated into the material, they cause its structure to buckle; this then gives the overall structure a higher capacity than other 2D materials. This buckling, which is seen in other 2D materials like germanene, manifests itself as a phase transition when adsorption of more than one ion occurs on the surface. According to these calculations, this phase transition should be completely reversible, and aids the diffusion of ions away from the anode.
预计SI2BN具有通常的电子特性,使2D材料成为材料科学中极大兴奋的来源。亚博网站下载亚博老虎机网登录它坚固,灵活,具有可调的带隙,并且电子和热量都具有很高的电导率。SI2BN具有高电子迁移率的事实对于其作为阳极的有用性至关重要。这与以下事实结合在一起,即离子具有很高的扩散率,可以使电池迅速充电和放电。创建一个可以可靠地存储大量能量的快速充电电池对于在电网存储和备份以及电动汽车中的应用非常重要。
SI20亿章从未批量合成,尽管目前许多不同的团队可能正在努力创建这种2D材料。该领域的进展很快:几年前,硼苯被认为是一种有前途的阳极材料。几乎一旦成功合成(2015年),就报告了SI2BN可能超过其作为阳极的能力的第一个预测。这些电子特性的理论预测使材料科学家可以探索物理上可能的参数空间。亚博网站下载下一步将是构建电池原型以测试现场的阳极性能,然后改进电池以使隔离器不断变为离子存储的理论最大值。随着我们对更加宽敞和灵活的储能系统的需求增加,这种突破对于能够不断改进技术至关重要。
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