Using electrolytes containing lithium difluoroborate (oxalate) borate and lithium tetrafluoroborate salts for lithium metal and anodeless electrodes?
Written by Zhu Lin
Editor?/?Zhang?nan
Design?/?Du?kai
Source?/?electrek, author: Fred?Lambert
Tesla has applied for a patent for a new technology that would provide an electrolyte solution for a new metal lithium battery, or anode-less battery.
For the past year, Tesla’s battery research partner Jeff Dahn and his team at Dalhousie University have been working on Tesla’s Work to improve energy density and battery life while reducing costs.
Last year, they published test results of a new type of battery, a lithium-ion battery with a next-generation "single crystal" NMC (nickel cobalt manganese) cathode and a new Advanced electrolytes. Dahn's team has conducted extensive testing of the batteries, and based on the results, they believe they could power an electric vehicle for more than 1 million miles (1.6 million kilometers) and be used in grid energy storage for at least 20 years. It lasts two to three times longer than Tesla’s current battery.
They tested the batteries under different conditions and cycles. Even at extreme temperatures of 40 degrees Celsius, these batteries can last up to 4,000 cycles. With an active cooling system, like Tesla's battery packs, it can increase the battery's cycle count to over 6,000 times, meaning a good battery pack can easily last a million miles. Controlling charging to a state of charge below 100 also helps extend life. They believe the batteries will be particularly useful in "robo taxis".
As a pioneer in lithium-ion battery technology, Dahn and his team have been researching next-generation battery technology in addition to improving existing technology.
Last year, the team applied for a patent for Tesla’s “anodeless lithium metal battery,” which they believe could be the next big thing in battery technology to replace solid-state batteries. The team's paper essentially explains how they solved the problem of replacing traditional graphite anodes with lithium metal without the need for a solid electrolyte. If successful, it would enable the commercialization of batteries with higher energy density and longer durability in less time than solid-state batteries.
Now, a new patent filed by Dahn’s team for Tesla’s Canadian research team proves that they are still working on new batteries: “Electrolytes containing lithium difluoro(oxalate)borate and lithium tetrafluoroborate salts , for lithium metal and anodeless batteries."
Tesla writes in the patent application:
“Rechargeable batteries are ideal for electric vehicles and grid storage (e.g., backup power during power outages, as part of a microgrid, etc. ) are an integral component of energy storage systems. Some such rechargeable battery systems include lithium metal and anode-free lithium batteries, which have certain advantages over traditional lithium-ion batteries because. They have higher energy density. Since there is no anode coating, anode-free batteries are also cheaper and easier to assemble. However, challenges with lithium metal and anode-free lithium batteries prevent their widespread adoption. Certain properties will enable wider use of such systems. For example, the development of electrolyte compositions that enable commercially acceptable lithium metal cycling performance and anode-free lithium batteries will be critical to gaining adoption of such battery systems. Prior to this, the general consensus in the industry was that electrolytes containing only lithium difluoro(oxalate)borate ("LiDFOB") salts best improved the capacity retention capabilities of lithium metal and anode-free lithium batteries."
In short, this kind of battery has great advantages in terms of energy density and cost, but needs improvement in terms of life.
Dahn’s team says their new electrolytes will help improve this:
“The electrolytes provided contain lithium difluoro(oxalate)borate and lithium tetrafluoroborate , as well as solvent components for lithium metal or anode-free rechargeable batteries, and methods of using the electrolyte to improve battery capacity. Also provided are rechargeable battery systems including lithium metal or anode-free battery cells, and difluoride ( The electrolyte solution of lithium oxalate) borate and lithium tetrafluoroborate as well as the solvent components. The system described in this article has higher capacity retention capabilities."
In the patent application, they did publish test results showing that. The battery's capacity retention has been improved, but it currently doesn't seem to increase battery life beyond 50 cycles. They need to cycle the battery more before it can be commercialized.
Earlier this year, Tesla researchers published a study describing a new battery that leverages the longevity of lithium-ion batteries and the high energy density of lithium metal batteries. Use hybrid lithium metal batteries as a range tool for all-electric vehicles.
“Increasing the energy density of batteries will reduce the cost of electric vehicles and extend driving range. Replacing graphite anodes in traditional lithium-ion batteries with metallic lithium can significantly increase energy density. However, lithium metal anodes exist Problems of rapid capacity loss and short battery life. In order to develop long-life high-energy-density batteries, we propose a lithium-ion/metal lithium hybrid battery, which is achieved by purposely plating metal lithium on graphite. In lithium-ion batteries, excess lithium plating is usually a degradation mechanism, but we achieved reversible graphite lithium plating in an optimized dual-salt electrolyte. Additionally, since batteries are typically not cycled to 100% capacity, these hybrids are Batteries can operate in lithium-ion mode with little degradation, increasing capacity through periodic cycles of fully charged lithium metal."
However, it is important to note that, Tesla, like most other companies, sometimes patents technology that won't make it into production.
More information about Tesla’s battery plans will be announced during Battery Day on September 15.
This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.