The Aiiso Yufeng Li Family Department of Chemical and Molecular Engineering at the University of California San Diego and the UChicago Pritzker School of Molecular Engineering have recently collaborated to advance the development of high-capacity, fast-charging, and cost-effective batteries for electric vehicles and grid storage. Inexpensive fast charging high capacity batteries
Grayson Deysher, the first author of a new paper that delineates the team’s work, stated, “Although there have been previous sodium, solid-state, and anode-free batteries, no one has been able to successfully combine these three ideas until now.”.
Today’s Nature Energy paper presents a novel sodium battery architecture that sustains high cycling stability for several hundred cycles. This new battery will be more environmentally friendly and cost-effective to manufacture by eliminating the anode and utilizing inexpensive, abundant sodium in place of lithium. Its innovative solid-state design further guarantees the battery’s safety and power.
This work is both a scientific advancement and a critical step in the process of addressing the battery scaling gap that is required to transition the global economy away from fossil fuels.
“To keep the United States running for one hour, we must produce one terawatt hour of energy,” Meng pointed out. “In order to achieve our objective of decarbonizing our economy, we require several hundred terawatt hours of batteries.” We need additional batteries at an expedited rate.
Sustainability and Sodium
Lithium, which is usually used in batteries, is a very rare element found in about 20 parts per million of the Earth’s crust. Conversely, sodium makes up about 20,000 parts per million. The limited availability of lithium and the increasing demand for lithium-ion batteries in laptops, phones, and electric vehicles (EVs) have led to price rises, making these batteries increasingly less affordable.
The majority of the world’s lithium supply is concentrated in particular areas, mostly in the “Lithium Triangle,” which consists of Chile, Argentina, and Bolivia, with over 75% of the world’s lithium reserves concentrated. In the battle against climate change, this concentration of resources and efforts toward decarbonization unfairly benefits some countries over others.
Meng said: “Global action requires working together to access critically important materials.”
Furthermore, either the more common brine extraction method, which involves pumping vast amounts of water to the surface for evaporation, or the process of extracting lithium using industrial acids to break down mining ore, has major negative environmental consequences. Sodium, abundant in ocean water and soda ash mining, not only has natural environmental benefits but also, according to LESC research, has proven to be a highly effective material for batteries.
Innovative Architecture
In order to achieve the same energy density as a lithium battery, the team had to develop a novel architecture for a sodium battery. Conventional batteries contain an anode that stores ions during the charging process. When the battery is in use, the ions move from the anode through an electrolyte to a current collector, known as the cathode. This flow of ions powers devices and vehicles.
Anode-free batteries eliminate the anode and instead store ions by directly depositing alkali metal on the current collector through electrochemical means. This method allows for a higher voltage in the cell, reduces the cell’s cost, and increases the energy density. However, it also presents its own set of difficulties.
“In any anode-free battery, there needs to be good contact between the electrolyte and the current collector,” stated Deysher. “This is typically straightforward when using a liquid electrolyte, as the liquid can flow everywhere and wet every surface. A solid electrolyte cannot do this.” A solid electrolyte lacks the ability to perform this action. Nevertheless, the presence of liquid electrolytes leads to the formation of a solid electrolyte interphase, which gradually depletes the active materials and diminishes the battery’s long-term effectiveness.
A solid that flows
The team adopted an innovative approach to address this problem. Rather than employing an electrolyte that encircles the current collector, they devised a current collector that encloses the electrolyte. They constructed the current collector using aluminum powder, a solid material capable of exhibiting fluid-like behavior.
High pressure compressed the powder during the battery assembly process to form a solid current collector. At the same time, it maintained a liquid-like connection with the electrolyte. This allows for cost-effective and efficient cycling, which is crucial for advancing this groundbreaking technology.
Deysher stated, “We hope this paper can invigorate more push into the sodium area by demonstrating that it can indeed work well, even better than the lithium version in some cases.”
What is the ultimate objective? Meng envisions a future energy landscape characterized by a diverse range of affordable battery solutions capable of storing renewable energy at a scale that meets the requirements of society.
Meng and Deysher have submitted a patent application for their research through UC San Diego’s Office of Innovation and Commercialization.
