Coal anode 18650 lithium-ion X-BATTeries

Exploring the potential of alternative anode materials in lithium-ion batteries, X-BATT announced the successful completion of a project that demonstrates its coal material can hold its own amidst conventional graphite in lithium battery anodes.

"We are excited to have completed this project, which has the potential to make a huge impact," said X-BATT CEO Bill Easter. "The use of coal as a value-added material not only provides a domestic source for anodes but creates a new market for coal."

Founded in 2013, X-MAT, the advanced materials division of Semplastics, designed a revolutionary high-performance material that combines the properties of metal for its electrical conductivity, the lightweight characteristic of plastic, and the potent thermal stability of ceramics.

This seemingly miracle material – coal.

By combining powdered raw coal with a proprietary resin, X-MAT successfully created a material that is extraordinarily lightweight, roughly two times lighter than Teflon, and incredibly heat resistant, with an operating temperature of over 1,100 degrees Celsius (2,012 degrees Fahrenheit) with no degradation or loss of mass after burning, making its maximum operating temperature roughly two times higher than titanium, as a possible replacement for the critical graphite used in anode material in lithium-ion batteries.

With breakthroughs in battery chemistries and design, Semplastics launched X-BATT in 2019 after successfully utilizing coal as more than a heavy carbon fuel but as a possible abundant anode material to offset the demand for graphite and as a potential means to reduce the more-than-a-century of coal waste lying in heaps throughout the country.

18650 cells

An 18650 battery is a lithium-ion cell slightly larger than a typical AA battery. Its name derives from the battery's specific dimensions: 18 millimeters by 65 millimeters (for comparison, a AA battery is 14.5 millimeters by 50.5 millimeters).

These batteries are used in high-end flashlights, laptops, power tools, cameras, and even some electric cars because of their reliability, long run times, and ability to be recharged hundreds of times over.

18650 batteries are what the industry considers a "high drain battery." This means that they are designed to generate high output voltage and current to meet the stringent power demands of the specific portable electronic device in which it is being used.

Hence why these powerful little batteries are often utilized in more complex, power-hungry electronics that require a constant, high level of power for operation. As an added bonus, 18650 batteries have a high depth of discharge, meaning that they can be drained all the way down to 0% and still have the capability to fully recharge (generally not recommended, however).

First announced in February, X-BATT revealed its development of an 18650 battery utilizing the coal its sister company X-MAT had become familiar with through building materials.

You can read about the initial announcement of X-MAT's research into coal anode 18650 batteries at X-BATT reveals new coal anode material in the February 8, 2023 edition of Metal Tech News.

Over the course of a three-year project, with support from the Department of Energy and National Energy Technology Laboratory, the X-BATT team developed and tested its coal material in small, research-level coin cell batteries, which proved capable of successfully scaling up in production into industrial format 18650 batteries.

With a successful scale-up, then verification by third-party testing in partnership with the Battery Innovation Center, X-MAT has closed this chapter on its 18650 coal battery.

"We are grateful for the support of the Department of Energy and the NETL, who made this project possible," added Easter.

Over 1,000 cycles

The use of lithium-ion batteries has been growing rapidly, driven by demand for EVs and renewable energy storage. The anodes of these batteries rely on graphite that is almost exclusively imported from foreign countries, primarily China. However, X-MAT's research has demonstrated that coal could be a domestically sourced alternative or supplement to graphite as an anode active material.

With the Battery Innovation Center scaling and testing X-MAT's battery technology in 18650 cells, the latest milestone in development has demonstrated that the company's technology is commercially viable and can be produced on a large scale, utilizing existing equipment and processes.

For batteries, discharge capacity retention is the ability of a cell to retain power after many charge and discharge cycles. Through extensive testing, results from the first 18650 cells made with X-BATT's coal-resin showed a retention capacity of 80% after 1,000 cycles of being fully charged and discharged, highlighting their promising cycle life capabilities.

"We are thankful to have partnered with the Battery Innovation Center through this effort," said X-BATT Director of Battery R&D Kyle Marcus. "Their expertise and facilities were invaluable in making this project a success."

With a viable contender to take some of the pressure off graphite, X-BATT 18650 batteries may very well be appearing as a consumer product within the next few years. And with the company's capabilities in recycling graphite, it's not a stretch to say the company has possibly sought a method to rejuvenate its coal batteries in a similar fashion.

"The demand for lithium-ion batteries is going to continue to increase and is expected to outpace the supply of graphite," said Easter. "Our materials can meet this demand in a more eco-friendly way and should lead to a domestic source for anode materials, helping the U.S. reduce reliance on foreign countries for the critical materials needed to support the growing demand for electrification."