Lithium battery, sodium ion battery -Lithium - Ion Battery Equipment

The latest research and development trends of lithium batteries and sodium-ion batteries from the world's leading teams -Lithium - Ion Battery Equipment

In April last year, Lisa Smith, the author of this article, took a look at the latest lithium battery research results published in the "Advanced" magazine family. More than a year later, it looks like current research into battery technology will continue to expand, with many potential alternatives to lithium systems being actively sought. Now seems like a good time to share an update on our work on these new systems. But first, we need to take a quick look at the motivations behind this massive international effort:

Global energy demand is growing rapidly. Every time you pull out your smartphone, whether it's to check the weather to plant crops, get updates on bus schedules, or just to find out entertainment news about a celebrity, you're tapping into this energy Contribute to its use. It is widely accepted that sustainability is very important, but demand for certain raw materials is becoming unsustainable, particularly as changes in policy and the way we use technology drive a shift away from fossil fuels towards cleaner electrochemical systems transformation. Current commercial battery technology does not have or cannot meet the desired energy density (ie, the amount of energy that can be produced per gram of material).

To address key issues of sustainable energy generation and storage, researchers are exploring new materials as electrodes and electrolytes for batteries and creating new features such as flexibility or transparency in wearable or foldable devices.

The need for higher energy and power densities has spurred research into solid electrolytes, which may lead to more high-capacity lithium technologies beyond the standard. Researchers are currently studying three types of solid electrolytes: polymers, sulfides and oxides. Polymers are the easiest to work with but have lower mechanical strength and ionic conductivity than sulfides and oxides. Solid electrolytes need to be processed into very thin films to maximize current flow during charge/discharge, but achieving precise control during manufacturing has proven tricky.

A team working at several different institutions in the United States developed a β-Li3PS4 solid electrolyte membrane that is only 0.4 μm thick. These membranes are electrochemically compatible with metallic lithium anodes and do not require the high processing temperatures typical of sulfide-based solid electrolytes. Their three-step method, featured on the cover of Advanced Energy Materials, involves evaporation-induced face-to-face stacking assembly of Li3PS4˙2ACN (acetonitrile) nanosheets on a nickel substrate, producing a uniform film. Heating above 180°C removes ACN, provides good ionic conductivity, and converts the films to β-Li3PS4; applying 200MPa then melts the films, increasing their density. The discovery that the concentration of the precursor determines the membrane thickness provides a simple, tractable route to better control the formation of solid sulfide electrolyte membranes.(Lithium - Ion Battery Equipment)

Instead, to address the problem of lithium dendrite formation (a solution proposed by Zhang Qiang of Tsinghua University), a group from China designed what they call a "zipper-style" SEI film. Rather than suppressing stress-induced defects in the SEI layer, as most current methods do, these films are able to automatically repair cracks using self-healing mechanisms. In the journal Advanced Energy Materials, the research team explains how they patterned the anode surface with ordered pits to form a mesh-like SEI film that reduces polarization. This results in a more uniform lithium ion flux and improves performance during plating/stripping cycles.

The natural abundance of calcium has attracted another group of Chinese to research rechargeable calcium-ion battery systems. Among the multivalent cations under study, calcium has a reduction potential closest to that of lithium, and it exhibits greater safety and faster electrochemical kinetics; however, due to the slow diffusion of calcium from standard organic electrolytes into the active material, calcium The stability of the system is very poor (cycling stability is less than 50 cycles) and the operating voltage is very low.

Calcium ions are an interesting alternative to lithium ions, and this system is by far the most stable

Using expanded graphite electrodes: a material that allows Ca2 to be embedded rather than just plated and stripped from metallic calcium electrodes, the researchers developed a system with a carbonate electrolyte and Ca(PF6)2. Their paper in Advanced Science tells how they achieved a specific capacity of 66mAhg-1 at a current rate of 2C, with a high operating voltage of 4.6V. Crucially, their calcium-ion battery maintained a discharge capacity of 62 mAh g-1 after 300 cycles (at a charge retention rate of 94%), which is the most stable performance demonstrated by a calcium system to date.



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