A German-led research consortium has produced battery electrodes up to four times thicker than those in conventional cells, a change it says raises cell-level energy density by 10% to 15% without adding weight.
The group, headed by the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE), demonstrated the approach in lithium-ion, sodium-ion and zinc-ion cells, and built working lithium-ion pouch-cell prototypes to prove the concept.
Oliver Fitz, group leader for battery cell technology at Fraunhofer ISE, explained that the team increased electrode coating thickness from the usual 100 µm to 200 µm up to as much as 800 µm. Thicker electrodes mean a cell needs fewer current collectors, freeing space and weight for the material that actually stores energy.
The three chemistries were not treated as equals. Lithium-ion was taken furthest, to physical pouch-cell prototypes, while sodium-ion and zinc-ion were used to show the electrode design transfers across materials. That breadth matters for European manufacturing strategy: sodium-ion and zinc-ion both rely on abundant, low-cost inputs and are seen as candidates to ease dependence on imported lithium supply chains.
The new cells also drop two of the industry’s more contentious inputs. They are manufactured without toxic solvents and are PFAS-free, avoiding the so-called “forever chemicals” that have come under tightening EU scrutiny.
Fraunhofer ISE framed the work as a route to cheaper local manufacturing, not just a lab result. The institute said the cell architecture was “developed with future mass production in mind,” arguing that a potential electrode production line would be significantly less complex than today’s wet-coating systems. Lower complexity, it added, translates into lower capital costs and lower running costs, because the process needs less floor space and less energy.
That framing points squarely at small and medium-sized enterprises. “This technology thus opens up the possibility, particularly for small and medium-sized enterprises, to establish their own battery cell production facilities in Germany,” the institute said in a statement.
For stationary storage buyers, the headline number is modest but meaningful: at cell level, 10% to 15% more energy in the same weight and volume could translate into smaller, lighter cabinets or longer-duration discharge for home and commercial systems. The institute stopped short of predicting pack- or system-level gains, which are typically diluted by housing, thermal management and power electronics.
The research sits inside three publicly funded projects: VORAN, focused on innovative sodium-ion storage for stationary and mobile use; INFAB, on zinc-ion batteries for stationary energy storage; and WinZIB2, a globally deployable zinc-ion battery system. Partners include Acp systems, Helmut Hechinger, the University of Stuttgart’s Institute for Photovoltaics, and the Karlsruhe Institute of Technology/Helmholtz Institute Ulm.
Andreas Bett, director of Fraunhofer ISE, tied the work to the needs of a renewables-heavy grid. In a climate-neutral energy system with fluctuating sources such as solar and wind, he said, stationary battery storage is an integral component for covering the morning and evening electricity peaks.
“Germany would be well advised to build up manufacturing capacity to meet the growing demand for batteries and thereby create value within the country,” Bett said.
pv magazine — New electrode design increases battery energy density by up to 15% (2026-09-09)
