Researchers have developed a microbial-infused cement that functions as a supercapacitor, capable of storing energy and partially regenerating its performance after microbial reactivation.
Study: Living microbial cement supercapacitor with reactivatable energy storage. Image Credit: Nature Peaceful/Shutterstock.com
Published in Cell Reports Physical Science, the study presents a new way to integrate energy functionality directly into construction materials by embedding electroactive microbes into cement. This approach creates a biohybrid system that maintains structural integrity while offering energy storage capabilities and the unique ability to regain performance when supplied with nutrients. The innovation opens up promising possibilities for self-sustaining infrastructure that does more than just support buildings—it helps power them too.
Background
The push for more sustainable and cost-effective energy storage has exposed the limitations of conventional technologies like lithium-ion batteries, which face challenges related to resource scarcity, cost, and environmental impact. As researchers look for alternatives, cement—a material used globally at massive scale—has emerged as a surprising candidate for supercapacitor applications.
Previous studies have shown that cement can support electrostatic charge storage, but its overall performance has remained limited. To overcome this, the current research explores the potential of integrating electroactive microorganisms (EAMs), such as Shewanella oneidensis, into cement.
These microbes are capable of extracellular electron transfer (EET), essentially moving electrons between their own cells and the materials around them. While this mechanism has been studied in microbial fuel cells, its application in energy storage within structural materials has remained largely unexplored.
This study takes that next step, proposing a new type of cement composite that combines microbial redox activity with the durability and load-bearing properties of traditional concrete.
We’ve combined structure with function. The result is a new kind of material that can both bear loads and store energy - and which is capable of regaining its performance when supplied with nutrients.
Qi Luo, lead researcher of the team from Aarhus University
Study Design and Methods
To test their concept, the research team incorporated varying concentrations of S. oneidensis MR-1 (ranging from 0.3 % to 3 %) into cement pastes. These modified samples were paired with custom-fabricated electrode sheets made from graphene and carbon black, and stainless steel was used as the current collector. Sodium sulfate served as the electrolyte for electrochemical testing.
A combination of analytical techniques was used to assess the properties of the cement composites. These included:
- Fourier Transform Infrared Spectroscopy (FTIR) for molecular composition
- X-ray diffraction to identify mineral phases
- Thermogravimetric analysis (TGA) to monitor thermal stability
- Mercury intrusion porosimetry for pore distribution
- Scanning electron microscopy (SEM) to visualize microstructure and microbial encapsulation
Electrochemical performance was measured using:
- Cyclic voltammetry (CV)
- Electrochemical impedance spectroscopy (EIS)
- Galvanostatic charge–discharge (GCD) tests
These methods allowed the researchers to evaluate key parameters such as capacitance, energy and power density, and charge transfer resistance. Long-term cycling tests were conducted to assess durability, while a microfluidic system was used to simulate nutrient delivery for microbial reactivation.
Key Findings
Initial microstructural analysis showed that embedding EAMs had a minimal effect on early-stage cement hydration. However, over time (specifically by day 28), microbial activity led to the formation of calcium carbonate crystals, which helped densify the matrix and enhance mechanical properties.
Compressive strength tests confirmed that the cement composites retained structural integrity and even improved in strength beyond the 28-day mark. SEM images revealed that microbes were successfully integrated into the cement and formed interconnected networks, contributing to both mechanical stability and enhanced electrical conductivity.
Electrochemical testing highlighted the stark difference between microbial and control samples. While control specimens showed negligible charge storage, the EAM-infused cement demonstrated substantial gains. The best performance was observed at 1.2 % microbial concentration, achieving:
- Specific capacitance: ~1266 F/g
- Energy density: 178.7 Wh/kg
- Power density: 8.3 kW/kg
These values exceed those reported for conventional cement-based supercapacitors and are even competitive with some lithium-ion capacitor technologies. Interestingly, increasing the microbial concentration beyond 1.2 % led to a decline in performance, likely due to microbial aggregation, which disrupted the conductive pathways in the cement matrix.
Durability and Regeneration
Beyond performance, the microbial cement also demonstrated impressive longevity. After 10,000 charge–discharge cycles, the system retained 85 % of its capacitance. However, the microbes’ activity was sensitive to temperature. Peak charge transfer occurred at 33 °C, while both cold and high-heat environments suppressed metabolic function.
Importantly, even when the microbes became inactive, their residual biofilms and nanowires continued to contribute to partial energy storage, highlighting the hybrid nature of the system as both biological and material.
To test the material’s reactivability, the researchers introduced nutrients to aged and dormant composites. After two months of inactivity, nutrient supply alone restored about 18 % of the original capacitance. When fresh microbes were introduced along with nutrients, the system regained nearly 80 % of its capacity, demonstrating a self-renewal feature not found in conventional supercapacitors.
Implications and Next Steps
This research marks a shift in how we think about construction materials. Cement, traditionally viewed as inert and purely structural, can now be seen as a living component of energy systems, capable not only of storing charge but also of recovering functionality with minimal intervention.
The work also illustrates the growing synergy between microbiology, materials science, and civil engineering. Future research will need to focus on improving microbial resilience in highly alkaline environments, refining nutrient delivery systems, and evaluating cost and scalability for real-world applications.
If successful, microbial cement could lead to infrastructure that supports itself structurally and energetically—buildings that don’t just stand, but store.
Reference
Luo, Q., Li, Z., Li, Y., & Petrov, M. (2025). Living microbial cement supercapacitor with reactivatable energy storage. Cell Reports Physical Science, 6(9). DOI: 10.1016/j.xcrp.2025.102810. https://www.sciencedirect.com/science/article/pii/S2666386425004096
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