Researchers at the Max Planck Institute for Medical Research have unveiled a groundbreaking battery technology that promises significantly more powerful and energy-dense batteries.
A team led by Max Planck Director Joachim Spatz has discovered that utilizing metal fleeces as contact material in battery electrodes can dramatically accelerate charge transport and enable the construction of electrodes up to ten times thicker than current standards.
This innovation could lead to an 85% increase in energy density and significantly benefit industries ranging from electric vehicles to portable electronics.
A previously unknown mechanism
“The basis for this is a previously unknown mechanism that we discovered in ion transport in electrodes,” said Joachim Spatz.
Traditionally, battery electrodes consist of an active material, which stores the charge, and a contact material – typically copper or aluminium foil – which transports the current. However, the active materials, while good at storing charge, are poor ion conductors.
“This presents battery manufacturers with a dilemma: Either they make the electrodes thick so that their energy density is as high as possible, but then the batteries in question cannot be charged and discharged quickly. Or they make the electrodes extremely thin and accept that the energy density will decrease in order to achieve rapid charging and discharging,” explained the researchers in a press release.
Current electrodes are typically around a tenth of a millimetre thick.
The Heidelberg team’s research demonstrates that metal surfaces can act as “motorways” for metal ions. They found that lithium ions shed their molecular shell on a copper surface, forming an electrical double layer known as the Helmholtz layer.
“Using a specially developed measurement setup and theoretical calculations, we have shown that the lithium ions move through the Helmholtz layer around 56 times faster than through the electrolyte,” highlighted Spatz.
Innovative electrode design and performance
By interspersing the active material with a metallic fleece network made of threads just a few hundredths of a millimetre thick, the researchers created a 3D supply network for charge carriers.
This design not only allows for electrodes ten times thicker than conventional ones while maintaining fast charging and discharging capabilities suitable for electric cars, but it also uses approximately half the amount of contact metal and other non-storage materials.
The result is a remarkable up to 85% increase in energy density compared to traditional foil electrodes.
“Supplying a material with charge via two-dimensional layers is in no way efficient,” noted Spatz, drawing an analogy to nature’s three-dimensional vascular networks.
“That is the goal of our technology: A 3D supply network for charge carriers that can be used to charge and discharge batteries efficiently.”
Saving production cost
Beyond the performance boost, the new fleece electrodes also offer significant manufacturing advantages.
The current complex and sometimes toxic solvent-based process of applying thin layers of active material to foils can be replaced by introducing the active material into the fleeces in powder form.
“With dry filling, we can probably save 30 to 40 percent of production costs, and the production facilities need a third less space,” estimated Spatz.
Spatz believes this innovation could significantly enhance the competitiveness of manufacturers in the rapidly evolving battery technology landscape.
“With our technology, we have the chance to catch up with Asian manufacturers and be even better,” Spatz concluded.
