Researchers have found that a special zinc additive enhances the performance of thin lithium metal strips and prevents structural degradation in the quest for scalable production of high-performance anodes for lithium-ion batteries.
A research team led by scientists from Central South University, Changsha, Hunan, China have used the Australian Synchrotron in developing a novel strategy for the scalable production of high-performance, thin, and free-standing lithium anodes for lithium-ion batteries with enhanced cycling stability and electrochemical properties.
The Australian Synchrotron is a major research facility located in Clayton, a technology and innovation hub of southeast Melbourne. It is one of Australia’s most significant pieces of scientific infrastructure.
In 2013, Australia’s Nuclear Science and Technology Organisation (ANSTO) became the new operator of the Australian Synchrotron, which brought together two of the nation’s most significant pieces of scientific infrastructure to advance science outcomes for the nation.
According to ANSTO, the work being undertaken by scientists is to meet the growing demand for high-performance lithium-ion batteries.
ANSTO says solid-state lithium metal has a high energy density and high capacity theoretically, making it an ideal replacement for traditional graphite anodes.
“The team produced thin lithium strips with thicknesses ranging from 5 to 50 micrometres, with better mechanical strength, electrochemical performance and impressive cycling stability compared to untreated lithium strips“
In a paper published in Nature Communications, the team reports that a special zinc additive dialkyl dithiophosphate (ZDDP) enhanced the performance of thin lithium metal strips.
ANSTO notes that the research demonstrates that the additive increased hardness at the interface, prevented structural degradation (growth of lithium dendrites), controlled the deposition of lithium during plating/stripping, and the lithium anode could be plated and stripped faster than other materials.
“The team produced thin lithium strips with thicknesses ranging from 5 to 50 micrometres, with better mechanical strength, electrochemical performance and impressive cycling stability compared to untreated lithium strips.”
ANSTO says that a cycle lifetime of up to 2,800 hours was maintained even at a high area capacity. Additionally, a symmetrical cell based on ultrathin lithium strips with 15 micrometres thickness lasted for more than 800 hours.
The study also included a full cell configuration using LiFePO4(LFP) and ZDDP-coated lithium, showing excellent cycling life with over 83.2% capacity retention after 350 cycles. In comparison, a cell without ZDDP degraded rapidly.
The improved electrochemical characteristics of the ZDDP-coated lithium anode were attributed to the creation of a high-strength artificial solid electrolyte interface (SEI) layer with a high affinity for lithium.
Instrument scientist Dr Bernt Johannessen says this was an example of innovative work in the development of ultra-thin lithium, only microns thick that is manufactured for solid-state batteries.
For the study, a zinc-based oil was developed and used during the production process, in which the lithium is rolled out thinner and thinner, similar to how you roll dough through a pasta machine.
Samples were mailed to the synchrotron, and Dr Johannessen undertook the measurements of the lithium anodes using the X-ray absorption spectroscopy beamline, which has proved particularly useful in investigating energy materials and catalysis.
The beamline produced nearly twice the number of publications through 2023 as compared to the previous year.
Beaming with pride
Johannessen adds: “On that note, we owe our user community a debt of gratitude; they are being wonderfully productive and taking full advantage of recent developments, such as fast scanning techniques, at the beamline.”
Dr Zhibin Wu, the second author, was a recipient of the AINSE Postgraduate Research Award recipient and studied under the co-supervision of Dr Bernt Johannessen during his PhD at the University of Wollongong.
A synchrotron is a very large, circular, gigavolt technology about the size of a football field. From outside, the Australian Synchrotron, for example, looks like a roofed football stadium. But on the inside, it’s very different. Instead of grass and seating, there is a vast circular network of interconnecting tunnels and high tech apparatus.
Synchrotrons use electrons to produce intense beams of light more than a million times brighter than the sun. The light is produced when high-energy electrons are forced to travel in a circular orbit inside the synchrotron tunnels by the ‘synchronised’ application of strong magnetic fields.
The electron beam travels just under the speed of light – about 299,792km a second. The intense light they produce is filtered and adjusted to travel into an experimental workstation, where light reveals the innermost, sub-macroscopic secrets of materials, from human tissue to plants to metals and more.
The synchrotron produces X-ray and infrared radiation that is channelled down long pipelines, known as beamlines, into a suite of scientific instruments.
Write to Adam Orlando at Mining.com.au
Images: ANSTO
