Researchers at Yokohama National University have found that a porous form of carbon called graphene mesosponge can improve both the energy density and power density of commercial lithium-ion batteries. The findings were published in the journal Advanced Energy Materials on October 8, 2026.
Lithium-ion batteries power everything from smartphones and laptops to electric vehicles, and engineers are working to make them hold more energy. The main limit lies in the positive electrode, which restricts how much energy a battery can store. Some researchers have explored pure nickel oxide as a higher-energy alternative, but high voltages degrade it, making it harder for the battery to charge and discharge.
A common strategy is to pack more active material into the electrode while removing the components that do not store electricity, such as conductive additives and polymer binders. That approach has a drawback. A densely packed electrode with little conductive material becomes a tangle through which electricity and lithium ions struggle to pass. “Achieving efficient electron and ion transport in high-loading, densely packed electrodes remains a major challenge for high-energy-density lithium-ion batteries,” said Naoaki Yabuuchi, a professor at Yokohama National University.
Testing Three Carbon Materials
To tackle this problem, the team compared three carbon materials as possible conductive additives: acetylene black, single-walled carbon nanotubes, and graphene mesosponge. The researchers found that graphene mesosponge performed best because its sponge-like, porous framework shapes the electrode’s internal structure. Adding only a small amount formed three-dimensional networks that conduct both electrons and ions.
The porous structure also allows the electrolyte, the liquid that carries lithium ions, to reach deep into the parts of the electrode where energy is stored. The electrolyte held within the material’s tiny pores helps ions move quickly, which allows the battery to perform well at high current densities.
To confirm these effects, the team used a 3D imaging technique called FIB-SEM tomography. The images showed that graphene mesosponge creates a more evenly distributed internal structure throughout the electrode.
Next Steps
Yabuuchi described the results in strong terms. “Our results demonstrate that graphene mesosponge is a transformative conductive additive for simultaneously improving energy and power densities in practical lithium-ion batteries through rational microstructural design of dense composite electrodes,” he said.
The team’s next goal is to achieve fast charging with a graphite negative electrode. Success would allow batteries that combine high energy density, high power density, and fast charging, although that work has not yet been completed.
