Application of lithium-metal anodes for secondary batteries

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Society needs a high energy density battery system, and as a high energy density battery, lithium metal batteries have attracted a lot of attention.

Radar plots of performance properties of stabilized lithium metal powder (SLMP), stabilized lithium metal anode (SLMA), deposited lithium metal anode (DLMA), lithium metal composite anode (CLMA) and lithium-metal anode without anode (AFLMA). Image credit: © Science China Press.

The lithium metal electrode contains a low electrode potential and can express a capacity of up to 3860 mAh g-1. In addition to high energy density, lithium metal anodes have great application potential.

But there are difficulties associated with improving practical lithium metal batteries because the lithium metal anode in lithium metal batteries is highly reactive, which may have safety implications.

At Fudan University, Xiaoli Dong and Yongyao Xia et al. reported a review article in the National Science Review.

The study considered failure mechanisms and current research on practical lithium metal anodes, providing designs for future study.

Generally, the utilization efficiency of lithium metal is low in lithium metal batteries, which greatly shortens its service life. Lithium metal exhibits high reactivity and is also sensitive to air and moisture, which causes them to fail and pose safety concerns.

Two significant failure modes (short circuit and loss of capacity) of lithium metal anodes have been analyzed by scientists. Lithium dendrite is the main cause of short circuit: conditions such as non-uniform distribution of lithium-ion concentration would rationalize the growth of lithium dendrite, which could enter through the separator and cause a short circuit.

Primarily, the capacity decay comes from irreversible reactions of lithium metal with lithium metal dust and electrolytes. Due to the high reactivity of lithium metal, a certain amount of active lithium metal would react with the electrolyte and cause capacity degradation.

At the same time, a dusting of lithium metal during the charging and discharging process would increase the consumption capacity and the impedance of the batteries. After discovering two important failure mechanisms of lithium metal anodes, the scientists were able to investigate more purposefully and design more practical lithium metal anodes.

Later, scientists reviewed and reviewed this targeted work. Depending on manufacturing methods and equivalent applications, five categories of lithium anodes are offered: stabilized lithium-metal powder anode (SLMP), deposited lithium-metal anode (DLMA), lithium-metal composite anode (CLMA), anode lithium-metal (SLMA) and lithium-metal anode without anode (AFLMA).

Opportunities for practical application of such anodes are evaluated by comparing their advantages and disadvantages. SLMP can skillfully compensate for the irreversible capacity of commercial anodes like graphite; SLMA can effectively prevent dusting of lithium metal and straighten dendrites.

DLMA skillfully regulates the presence of the anode interface. However, it is complex to achieve; CLMA can develop a reliable electrode structure, avoiding a complex preparation process. AFLMA uses copper as an anode, streamlining the battery manufacturing process.

Decisively, SLMA could be considered the most promising and practical lithium metal anodes among the five anodes reviewed; and SLMP may be the leading candidate for high energy density lithium metal batteries.

There is still a large gap between current technology and practical lithium metal anodes, even though lithium metal anodes have been thoroughly and comprehensively analyzed by current research.

As the growth of advanced characterization and manufacturing techniques progresses, lithium metal battery mechanisms will be more elaborately analyzed and preparation techniques will be improved. Keeping this in mind, the company is not so far from the advent of safe and energy-dense lithium metal batteries, which can drive the energy revolution.

Journal reference:

Lip., et al. (2022) The way to the practical application of lithium-metal anodes for non-aqueous secondary batteries. National Science Review. doi.org/10.1093/nsr/nwac031.

Source: https://www.scichina.com/

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