On March 22, a team led by the University of Glasgow (UOG) in the United Kingdom used plant starch and carbon nanotubes as electrode materials to create a new type of lithium battery using 3D printing technology. This will provide a greener, higher-capacity power source for mobile devices. Relevant research results were published in "Power Supply Magazine".
Lithium-ion batteries are lightweight, compact, and have good cycling performance, making them ideal for use as power sources for laptops, mobile phones, smart watches, and electric vehicles. Lithium-ion batteries contain a positive electrode made of lithium cobalt, manganese oxide, or lithium iron phosphate, and a negative electrode made of metallic lithium. During charging, lithium ions flow from the positive electrode to the negative electrode through the electrolyte. During discharge, ions flow in the opposite direction, generating energy through an electrochemical reaction that powers the device.
Electrode thickness is one of the main physical factors affecting energy storage and release in Li-ion batteries. Thick electrodes not only limit the diffusion effect of lithium ions on the electrode, thereby limiting the specific energy of lithium-ion batteries, but also reduce the strain tolerance of the battery, making it more prone to failure due to cracking.
The battery designed by UOG aims to create a better balance between electrode size and electrode surface area by introducing nanoscale pores. The surface area of microporous electrodes is significantly increased compared to solid electrodes of equal external dimensions. To do this, the researchers used 3D printing, known as additive manufacturing, to precisely control the size and location of the micropores on the electrodes. 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 (3% to 10% carbon nanotube content) and different microporosity (10% to 70%). The results show that the electrode with a thickness of 300 microns and a microporosity of 70% has the best performance, and its specific energy is 151mAh·g-1, which is about 2~3 times the capacity of traditional lithium-ion batteries using solid electrodes of the same thickness. This optimization method also solves the problem caused by the electrode thickness. Compared with the 100-micron-thick electrode, the storage capacity of the 300-micron-thick electrode was increased by 158%.
Dr Shanmugam Kumar, author of the paper and project leader, said: "Lithium-ion batteries already occupy an important place in daily life. With further electrification and sustainable development, their importance will continue to increase. However, lithium-ion batteries themselves have Sustainability issues cannot be ignored. In this study, we used a 3D printing process to precisely control the microporosity of the electrodes, which to some extent compensated for the shortcomings of existing lithium-ion batteries. We hope to continue exploring this microstructure The potential applicability of electrode materials, and then develop a recyclable lithium battery with better performance and easier recovery." Science Grand View Garden Magazine