Green Highly Efficient And Economical Method Released For Recycling LCO And Ternary LIBs

| Jerry Huang

Green Highly Efficient And Economical Method Released For Recycling LCO And Ternary LIBs

Editor's note: Lithium-ion batteries are now widely used in a variety of electronic devices, EV and grid-scale energy storage. Global demand for lithium-ion batteries continues to grow significantly. It is estimated that by 2030, the global volume of spent lithium-ion batteries will exceed 11 million tons, which will become a huge source of pollution that could seriously threaten the environment and public health. At the same time, the growing demand for lithium-ion batteries translates into a growing demand for lithium and cobalt. On the other hand, the content of lithium and cobalt in LIB cathodes is as high as 15% and 7% wt, respectively, which is much higher than that in ores and brines. Therefore, the recovery of metal elements in spent LIB cathodes is of great environmental, social and economic significance. Currently, the recovery of lithium-ion batteries is mainly divided into three steps: pretreatment, metal extraction and metal separation. In the research and development of the metal extraction step of the recycling process, the hydrometallurgical process is one of the most viable options because of its high metal leaching rate and satisfactory purity of the recovered products. However, the process is not so environment friendly, nor highly economical, because the use of inorganic acids brings hazardous by-products; while organic acids require additional reducing agents or longer reaction times and higher temperatures for metal recovery.

Researchers from Zhong Lin Wang team bring us a possible method that is green, highly efficient and economical for recycling LIBs, including lithium cobalt oxide batteries (LCO) and ternary lithium batteries.

Abstract

With the global trend towards carbon neutrality, the demand for lithium-ion batteries (LIBs) is continuously increasing. However, current recycling methods for spent LIBs need urgent improvement in terms of eco-friendliness, cost and efficiency. Here we propose a mechano-catalytic method, dubbed contact-electro-catalysis, utilizing radicals generated by contact electrification to promote the metal leaching under the ultrasonic wave. We also use SiO2 as a recyclable catalyst in the process. For lithium cobalt (III) oxide batteries, the leaching efficiency reached 100% for lithium and 92.19% for cobalt at 90 °C within 6 hours. For ternary lithium batteries, the leaching efficiencies of lithium, nickel, manganese and cobalt reached 94.56%, 96.62%, 96.54% and 98.39% at 70 °C, respectively, within 6 hours. We anticipate that this method can provide a green, high efficiency and economic approach for LIB recycling, meeting the exponentially growing demand for LIB productions.

Reference

https://doi.org/10.1038/s41560-023-01348-y

An Efficient Green And Economical Method Released For Recycling LFP Batteries

| Jerry Huang

An Efficient Green And Economical Method Released For Recycling LFP Batteries

Editor's note: Lithium-ion batteries are now widely used in a variety of electronic devices, EV and grid-scale energy storage. Global demand for lithium-ion batteries continues to grow significantly. It is estimated that by 2030, the global volume of spent lithium-ion batteries will exceed 11 million tons, which will become a huge source of pollution that could seriously threaten the environment and public health. At the same time, the growing demand for lithium-ion batteries translates into a growing demand for lithium and cobalt. On the other hand, the content of lithium and cobalt in LIB cathodes is as high as 15% and 7% wt, respectively, which is much higher than that in ores and brines. Therefore, the recovery of metal elements in spent LIB cathodes is of great environmental, social and economic significance. Currently, the recovery of lithium-ion batteries is mainly divided into three steps: pretreatment, metal extraction and metal separation. In the research and development of the metal extraction step of the recycling process, the hydrometallurgical process is one of the most viable options because of its high metal leaching rate and satisfactory purity of the recovered products. However, the process is not so environment friendly, nor highly economical, because the use of inorganic acids brings hazardous by-products; while organic acids require additional reducing agents or longer reaction times and higher temperatures for metal recovery.

Researchers from Zhong Lin Wang team bring us a possible method that is green, highly efficient and economical for recycling LIBs, especially LFP batteries.

Abstract

The recycling of lithium iron phosphate batteries (LFPs), which represent more than 32% of the worldwide lithium-ion battery (LIB) market share, has raised attention owing to the valuable element resources and environmental concerns. However, state-of-the-art recycling technologies, which are typically based on electrochemical or chemical leaching methods, have critical issues such as tedious procedures, enormous chemical/electricity consumption and secondary pollution. Here, we report an innovative self-powered system composed of an electrochemical LIB recycling reactor and a triboelectric nanogenerator (TENG) for recycling spent LFP. In the electrochemical LIB recycling reactor, the Cl−/ClO− pair generated electrochemically in NaCl solution is adopted as the redox mediator to break down LFP into FePO4 and Li+via the redox targeting reaction without extra chemicals. Additionally, a TENG that utilizes discarded components from LIBs including casings, aluminum-plastic films and current collectors is designed to drastically minimize secondary pollutants. Furthermore, the TENG harvests wind energy, delivering an output of 0.21 W for powering the electrochemical recycling system and charging batteries. Therefore, the proposed system for recycling spent LFP exhibits high purity (Li2CO3, 99.70% and FePO4, 99.75%), self-powered features, simplified treatment procedure and a high profit, which can promote the sustainability of LIB technologies.

Reference

http://dx.doi.org/10.1039/D3EE01156A

50C Fast-charge Li-Ion Batteries Using a Graphite Anode

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50C Fast-charge Li-Ion Batteries Using a Graphite Anode

Abstract

Li-ion batteries have made inroads into the electric vehicle market with high energy densities, yet they still suffer from slow kinetics limited by the graphite anode. Here, electrolytes enabling extreme fast charging (XFC) of a microsized graphite anode without Li plating are designed. Comprehensive characterization and simulations on the diffusion of Li+ in the bulk electrolyte, charge-transfer process, and the solid electrolyte interphase (SEI) demonstrate that high ionic conductivity, low desolvation energy of Li+, and protective SEI are essential for XFC. Based on the criterion, two fast-charging electrolytes are designed: low-voltage 1.8 m LiFSI in 1,3-dioxolane (for LiFePO4||graphite cells) and high-voltage 1.0 m LiPF6 in a mixture of 4-fluoroethylene carbonate and acetonitrile (7:3 by vol) (for LiNi0.8Co0.1Mn0.1O2||graphite cells). The former electrolyte enables the graphite electrode to achieve 180 mAh g−1 at 50C (1C = 370 mAh g−1), which is 10 times higher than that of a conventional electrolyte. The latter electrolyte enables LiNi0.8Co0.1Mn0.1O2||graphite cells (2 mAh cm−2, N/P ratio = 1) to provide a record-breaking reversible capacity of 170 mAh g−1 at 4C charge and 0.3C discharge. This work unveils the key mechanisms for XFC and provides instructive electrolyte design principles for practical fast-charging LIBs with graphite anodes.

References

  1. https://doi.org/10.1002/adma.202206020

High-Voltage High-Energy-Density Li-ion Battery Reported To Be Cheap And Metal-free

| Jerry Huang

High-Voltage High-Energy-Density Li-ion Battery Reported To Be Cheap And Metal-free

Editor’s note: Researchers report a breakthrough high-voltage high-energy-density electrochemistry of Lithium-ion Battery that is economical and metal-free (environment-friendly). This 4 V-class organic lithium-ion battery features high theoretical capacity and high voltage, while their practical cathode materials and electrolytes remain unexplored.

Are Redox-Active Organic Small Molecules Applicable for High-Voltage (>4 V) Lithium-Ion Battery Cathodes?

By: Yuto Katsuyama, Hiroaki Kobayashi, Kazuyuki Iwase, Yoshiyuki Gambe, Itaru Honma | First published: 10 March 2022 on Advanced Science

4 V-Class Organic Lithium-Ion Batteries

While organic lithium-ion batteries have attracted great attention due to their high theoretical capacities, high-voltage organic cathode materials remain unexplored. In article number 2200187, Yuto Katsuyama, Hiroaki Kobayashi, Itaru Honma, and co-workers report the electrochemistry of croconic acid at high voltage. Theoretical and experimental investigations confirm the two enolates in croconic acid show around 4 V redox, which can be utilized for energy storage.

Abstract

While organic batteries have attracted great attention due to their high theoretical capacities, high-voltage organic active materials (> 4 V vs Li/Li+) remain unexplored. Here, density functional theory calculations are combined with cyclic voltammetry measurements to investigate the electrochemistry of croconic acid (CA) for use as a lithium-ion battery cathode material in both dimethyl sulfoxide and γ-butyrolactone (GBL) electrolytes. DFT calculations demonstrate that CA dilitium salt (CA–Li2) has two enolate groups that undergo redox reactions above 4.0 V and a material-level theoretical energy density of 1949 Wh kg–1 for storing four lithium ions in GBL—exceeding the value of both conventional inorganic and known organic cathode materials. Cyclic-voltammetry measurements reveal a highly reversible redox reaction by the enolate group at ≈4 V in both electrolytes. Battery-performance tests of CA as lithium-ion battery cathode in GBL show two discharge voltage plateaus at 3.9 and 3.1 V, and a discharge capacity of 102.2 mAh g–1 with no capacity loss after five cycles. With the higher discharge voltages compared to the known, state-of-the-art organic small molecules, CA promises to be a prime cathode-material candidate for future high-energy-density lithium-ion organic batteries.

References:

  1. https://doi.org/10.1002/advs.202200187

A Breakthrough Technology of Low Temperature LFP Revealed

| Jerry Huang

A Breakthrough Technology of Low Temperature LFP Revealed

On April 15, an R&D team from Changzhou Liyuan New Energy Co made an announcement in Nanjing that the company had made a technological breakthrough on LFP cathode material, which significantly improved LFP’s performance, as well as charging rate, at low temperature.

An EV powered by conventional LFP battery has its own obvious disadvantage of range anxiety, that is, its range is often around 50% of its claiming NEDC / WLTP / EPA range at low temperatures such as -20℃.

The new LFP material, "LFP-1", is claimed to be developed by more than 20 R&D experts from its Shenzhen Research Center after more than 2,000 repeated experiments in eight years and the R&D team has won 5 patents with it.

The breakthrough performances of “LFP-1” are reported to be achieved by establishing high-speed lithium ion transport channels inside the cathode material together with state-of-the-art “energy spheres” technology; and the material features:

  • Increasing the discharge capacity rate of LFP battery from 55% to 85% at -20℃ degrees, and from nearly zero to 57% at -40℃ degrees.

  • Achieving a range of 500 kilometers in just 15 minutes’ 4C rate fast charging. In comparison, an EV powered by conventional LFP battery usually needs 40 minutes’ fast charge to achieve a range of about 550 kilometers.

Will Sodium Be The Next Solution?

| Jerry Huang

In 2020, EV market involvers were excitedly speculating that the cost decrease of lithium powered batteries would bring a rapid growth of EV sales worldwide, and truly it did.

When it comes to the first quarter of 2022, most of us are just not ready to meet the “March Madness”, said Mr. Jow Lowry from Global Lithium LLC, on a dramatic price increase of lithium carbonate and lithium hydroxide in February and early March. However he feels that high lithium prices are not going to create demand destruction from EV market. “We have high lithium prices because the lack of investment that has created the supply-demand imbalance. I do not believe that this is going to destroy demand. I believe it is, more correctly put, it’ll forward demand. The EV revolution is going to be limited in this decade by lack of lithium supply. There’s no question about that now,” says Mr. Jow Lowry.

Despite the record high lithium prices, many other battery materials, such as nickel, cobalt and aluminum, have also encountered a historical wave of price increase in Q1 this year, which resulted in continued battery cost increase and more than 20 OEM’s announcements of their EV price raise in March 2022.

So where is the lithium battery heading for? Some experts say that lithium batteries will go to medium-end and high-end EV, consumer electronics, electric marine vehicles and aerial vehicles, etc.

What about the entry-level of EV and energy storage? Will sodium chemistry batteries be another choice for them? There is abundant sodium and other resources on earth for sodium batteries, which is believed to be economical and environment-friendly. Are there any other battery solutions that are highly scalable? Let’s wait and see what research breakthroughs will come next.

Cell Chemistry Race: Lithium vs Sodium Systems

| Jerry Huang

Research devoted to room temperature lithium–sulfur (Li/S8) and lithium–oxygen (Li/O2) batteries has significantly increased over the past ten years. The race to develop such cell systems is mainly motivated by the very high theoretical energy density and the abundance of sulfur and oxygen. The cell chemistry, however, is complex, and progress toward practical device development remains hampered by some fundamental key issues, which are currently being tackled by numerous approaches.

Quite surprisingly, not much is known about the analogous sodium-based battery systems, although the already commercialized, high-temperature Na/S8 and Na/NiCl2 batteries suggest that a rechargeable battery based on sodium is feasible on a large scale. Moreover, the natural abundance of sodium is an attractive benefit for the development of batteries based on low cost components.

This review provides a summary of the state-of-the-art knowledge on lithium–sulfur and lithium–oxygen batteries and a direct comparison with the analogous sodium systems. The general properties, major benefits and challenges, recent strategies for performance improvements and general guidelines for further development are summarized and critically discussed. In general, the substitution of lithium for sodium has a strong impact on the overall properties of the cell reaction and differences in ion transport, phase stability, electrode potential, energy density, etc. can be thus expected.

Whether these differences will benefit a more reversible cell chemistry is still an open question, but some of the first reports on room temperature Na/S8 and Na/O2 cells already show some exciting differences as compared to the established Li/S8 and Li/O2 systems.

Rechargeable lithium-ion batteries (LIBs) have rapidly become the most important form of energy storage for all mobile applications since their commercialization in the early 1990s. This is mainly due to their unrivaled energy density that easily surpasses other rechargeable battery systems such as metal–hydride or lead–acid. However, the ongoing need to store electricity even more safely, more compactly and more affordably necessitates continuous research and development.

The need for inexpensive stationary energy storage has become an additional challenge, which also triggers research on alternative batteries. Major efforts are directed towards continuous improvements of the different Li-ion technologies by more efficient packaging, processing, better electrolytes and optimized electrode materials, for example. Although significant progress has been achieved with respect to the power density over the last years, the increase in energy density (volumetrically and gravimetrically) was relatively small. A comparison of different battery technologies with respect to their energy densities is shown in Figure 1.

Theoretical and (estimated) practical energy densities of different rechargeable batteries.

Figure 1: Theoretical and (estimated) practical energy densities of different rechargeable batteries: Pb–acid – lead acid, NiMH – nickel metal hydride, Na-ion – estimate derived from data for Li-ion assuming a slightly lower cell voltage, Li-ion – average over different types, HT-Na/S8 – high temperature sodium–sulfur battery, Li/S8 and Na/S8 – lithium–sulfur and sodium–sulfur battery assuming Li2S and Na2S as discharge products, Li/O2 and Na/O2 – lithium–oxygen battery (theoretical values include the weight of oxygen and depend on the stoichiometry of the assumed discharge product, i.e., oxide, peroxide or superoxide). Note that the values for practical energy densities can largely vary depending on the battery design (size, high power, high energy, single cell or battery) and the state of development. All values for practical energy densities refer to the cell level (except Pb–acid, 12 V). The values for the Li/S8 and Li/O2 batteries were taken from the literature (cited within the main text) and are used to estimate the energy densities for the Na/S8 and Na/O2 cells. Of the above technologies, only the lead acid, NiMH, Li-ion and high temperature Na/S8 technologies have been commercialized to date.

References:

  1. https://www.beilstein-journals.org/bjnano/articles/6/105

Lithium Tetrafluoroborate (LiBF4) as a Li-ion Battery Electrolyte Additive

| Jerry Huang

Lithium Tetrafluoroborate (LiBF4) as a Li-ion Battery Electrolyte Additive

Lithium tetrafluoroborate (LiBF4) used as an electrolyte additive to improve the cycling performance of LiNi0.5Co0.2Mn0.3O2/graphite cell (NMC532) at higher operating voltage is investigated.

With 1.0 wt% LiBF4 addition into the electrolyte, the capacity retention of lithium ion battery after 100 cycles was greatly improved from 29.2% to 90.1% in the voltage of 3.0 V–4.5 V. To understand the mechanism of the capacity retention enhancement at high voltage operation, the properties including the cell performance, the impedance behavior as well as the characteristics of the electrode interfacial properties are examined.

It is found that LiBF4 was likely to participate in the formation of interface film on both electrodes. The improved performances of the cell are attributed to the modification of interface layer components on graphite anode and LiNi0.5Co0.2Mn0.3O2 cathode, which leading to lower the interfacial impedance.

Source: Zuo, Xiaoxi & Fan, Chengjie & Liu, Jiansheng & Xiao, Xin & Wu, Junhua & Nan, Junmin. (2013). Lithium Tetrafluoroborate as an Electrolyte Additive to Improve the High Voltage Performance of Lithium-Ion Battery. Journal of the Electrochemical Society. 160. A1199-A1204. 10.1149/2.066308jes. https://iopscience.iop.org/article/10.1149/2.066308jes

Lithium difluorophosphate vs sodium difluorophosphate as Li-ion electrolyte additives

| Jerry Huang

Lithium difluorophosphate vs sodium difluorophosphate as Li-ion electrolyte additives

Lithium difluorophosphate (LiDFP, LFO) is greatly helpful as an electrolyte additive to enhance performances of li-ion battery’s cycle life and discharge capacity retention at high temperature, as well as reducing self-discharge. While sodium difluorophosphate has similar performance in NMC532 battery cell? Let’s take a look at a paper published on Journal of The Electrochemical Society in 2020.

Conclusion:Three new difluorophosphate salt electrolyte additives were synthesized and evaluated in NMC532/graphite pouch cells. Ammonium difluorophosphate (AFO) is readily prepared via a solid-state, benchtop reaction of ammonium fluoride and phosphorus pentoxide that requires only gentle heating to initiate. The best yield of sodium difluorophosphate (NaFO) in the present study was obtained by reacting difluorophosphoric acid and sodium carbonate in 1,2-diemethoxyethane over 3 Å molecular sieves, a very strong drying agent. Tetramethylammonium difluorophosphate (MAFO) was prepared from NaFO via cation-exchange with tetramethylammonium chloride.

NaFO is reported to be a very good electrolyte additive, with similar performance in NMC532/gr cells as the better known lithium difluorophosphate (LFO) additive, each showing ~90% discharge capacity retention after more than 1,500 cycles at 40 °C. The long-term stability during cycling between 3.0–4.3 V compares favorably with, but nonetheless is less than the 2%VC 1%DTD benchmark cells reported by Harlow et al., which have ∼94% capacity retention after 1,500 cycles. The beneficial nature of both additives is attributable to the difluorophosphate anion. In contrast, AFO and MAFO are found to be poor electrolyte additives. This is suggested to be due to the formation of lithium nitride for the former. It is unknown why tetramethylammonium cations have a negative effect on cell stability.

References:

  1. Synthesis and Evaluation of Difluorophosphate Salt Electrolyte Additives for Lithium-Ion Batteries, Journal of The Electrochemical Society, 2020 167 100538, David S. Hall, Toren Hynes, Connor P. Aiken and J. R. Dahn

LiFSI vs. LiPF6 in Li-ion Battery Electrolytes

| Jerry Huang

LiFSI vs. LiPF6 in Li-ion Battery Electrolytes

Will LiFSI replace LiPF6 in Li-ion battery electrolytes? Using the new salt lithium bis(fluorosulfonyl)imide (LiFSI) rather than lithium hexafluorophosphate (LiPF6) as an electrolyte improves the performance of Li-ion batteries with silicon anodes, according to a paper published in the Journal of the American Chemical Society by researchers in Europe.

Lithium bis(fluorosulfonyl)imide, commonly referred to as LiFSI, has the molecular formula F2LiNO4S2 and CAS number 171611-11-3. LiFSI appears to be white powder, with a molecular weight of 187.07, and a melting point between 124-128°C (255-262.4°F).

Compared to LiPF6, LiFSI not only enhances thermal stability in li-ion battery technology, but also gives better performance in terms of electrical conductivity, cycle life, and low-temperature. However, LiFSI may have certain corrosive effects on aluminum foil. Some academic papers show that the corrosion of aluminum foil mainly comes from FSI-ions in LiFSI, but this problem can be solved by additives such as fluorine-containing passivation aluminum foil additives.

The trend is quite certain that LiFSI is becoming one of the mainstream lithium salts for next generation electrolytes. Currently, ternary lithium batteries and LFP batteries are constantly being improved and iterated generation after generation that have higher requirements for energy density, high and low-temperature performances, cycle life, and charge and discharge rate performances.

Due to high technical difficulty in mass production and high cost, LiFSI has not been directly used as a solute lithium salt, but as an additive mixed with lithium hexafluorophosphate (LiPF6) for use in the electrolytes of power li-ion batteries especially. For example, LG Chem has been using LiFSI as an additive in their electrolytes for quite some time. As technology improves, more and more LiFSI will be added to electrolytes. It is believed that the cost of LiFSI will be lowered further with the scaling up of mass production. And as time passes, LiFSI has the potential to replace LiPF6 as the main lithium salt for power li-ion battery electrolytes.

Sources:

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