3月22日报道，英国格拉斯哥大学（UOG）领导的团队以植物淀粉和碳纳米管为电极材料，用3D打印技术制造了一种新型锂电池。这将为移动设备提供更环保、容量更大的电源。相关研究成果刊登在《电源杂志》中。

锂离子电池具有轻质、紧凑和循环性能较好等优点，非常适合用作笔记本电脑、移动电话、智能手表和电动汽车的电源。锂离子电池包含锂钴、锰氧化物或磷酸铁锂制成的正极，以及金属锂构成的负极。在充电过程中，锂离子通过电解液，从正极流向负极。在放电过程中，离子反方向流动，通过电化学反应产生能量，为设备提供动力。

电极厚度是影响锂离子电池储存和释放能量的主要物理因素之一。厚电极不仅会限制锂离子在电极上的扩散效果，进而限制锂离子电池的比能，还会降低电池的应变耐受性，使其更易因开裂而失效。

UOG设计的电池旨在通过引入纳米级微孔，在电极尺寸与电极表面积之间建立更好的平衡关系。与外部尺寸相等的固体电极相比，微孔电极的表面积得到显著增加。为此，研究人员使用3D打印（即增材制造）技术，对电极上微孔的尺寸和位置进行了精确控制。3D打印的原料主要为聚乳酸、锂-铁磷酸盐和碳纳米管。其中，聚乳酸是由玉米淀粉、甘蔗淀粉、甜菜淀粉加工而成的可生物降解材料，它有效提高了电池的可回收性。

研究人员测试了不同厚度（100、200和300微米）、不同材料组合（碳纳米管含量3%~10%）不同微孔率（10%~70%）的圆形电极的性能。结果表明，300微米厚度、70%微孔率的电极性能最好，其比能为151mAh·g-1，大约是使用同等厚度固体电极的传统锂离子电池容量的2~3倍。这种优化方式也解决了电极厚度带来的问题。相较于100微米厚的电极，300微米厚电极的储电容量提高了158%。

论文作者、项目负责人ShanmugamKumar博士说：“锂离子电池已经在日常生活中占据了重要地位。随着电气化和可持续化发展的深入，其重要性还将继续提升。然而，锂离子电池自身的可持续性问题不容忽视。在这项研究中，我们使用3D打印工艺对电极的微孔率进行了精确控制，一定程度上弥补了现有锂离子电池的缺陷。我们希望继续探索这种微结构电极材料的潜在应用性，进而开发出性能更优越、更易回收的可循环锂电池。”科学大观园杂志

Lithium ion batteries have the advantages of light weight, compactness and good cycle performance, and are very suitable for use as power supplies for laptops, mobile phones, smart watches and electric vehicles. The lithium ion battery comprises a positive electrode made of lithium cobalt, manganese oxide or lithium iron phosphate, and a negative electrode made of lithium metal. During charging, lithium ion flows from positive electrode to negative electrode through electrolyte. In the discharge process, ions flow in the opposite direction and generate energy through electrochemical reaction to provide power for the equipment.

Electrode thickness is one of the main physical factors affecting the energy storage and release of lithium ion batteries. The thick electrode will not only limit the diffusion effect of lithium ion on the electrode, thereby limiting the specific energy of the lithium ion battery, but also reduce the strain resistance of the battery, making it more vulnerable to failure due to cracking.

The battery designed by UOG aims to establish a better balance between electrode size and electrode surface area by introducing nano sized micropores. Compared with the solid electrode with the same external size, the surface area of the microporous electrode is significantly increased. To this end, the researchers used 3D printing (i.e. additive manufacturing) technology to precisely control the size and position of micro holes on the electrode. The raw materials for 3D printing are mainly polylactic acid, lithium iron phosphate and carbon nanotubes. Among them, polylactic acid is a biodegradable material processed from corn starch, sugarcane starch and beet starch, which effectively improves the recyclability of batteries.

The researchers tested the performance of circular electrodes with different thicknesses (100, 200 and 300 microns), different material combinations (carbon nanotube content 3%~10%) and different porosity (10%~70%). The results show that the electrode with a thickness of 300 μ m and a porosity of 70% has the best performance, and its specific energy is 151 mAh · g-1, which is about 2-3 times of the capacity of traditional lithium ion batteries using solid electrodes of the same thickness. This optimization method also solves the problem caused by electrode thickness. Compared with 100 μ m thick electrode, the storage capacity of 300 μ m thick electrode is increased by 158%.

Author Dr. Shanmugam Kumar, the project leader, said: "Lithium ion batteries have played an important role in daily life. With the deepening of electrification and sustainable development, their importance will continue to increase. However, the sustainability of lithium ion batteries cannot be ignored. In this study, we used 3D printing process to precisely control the porosity of electrodes, which to some extent makes up for the shortcomings of existing lithium ion batteries. We hope to continue to explore this micro junction The potential application of structured electrode materials will further develop recyclable lithium batteries with better performance and easier recycling. " Journal of Science Grand View Garden