Biocompatible zinc–oxygen battery powers implantable sensors safely inside the body
image: The GelMA-PLCL gel electrolyte developed in this study for implantable Zn-O2 batteries overcomes the critical limitations of conventional electrolytes, specifically leakage and toxicity, by effectively suppressing both Zn corrosion and parasitic byproduct formation. This biocompatible design not only ensures long-term operational stability but also enables direct integration with physiological sensors for continuous vital sign monitoring.
Credit: Nano research, Tsinghua University Press
From cardiac pacemakers to physiological monitors, implantable medical devices have revolutionized modern healthcare. However, their reliance on conventional batteries remains a critical limitation. Existing batteries often suffer from insufficient biocompatibility and limited energy density, necessitating repeated and invasive replacement surgeries. To overcome these challenges, researchers in China have developed a biocompatible zinc–oxygen (Zn–O2) battery that can operate safely and stably inside the body, demonstrating its ability to power implantable sensors for continuous physiological monitoring.
“Our design transforms the body’s own oxygen and ions into part of the energy system,” says corresponding author Xizheng Liu, who studies implantable energy materials at Jianghan University. “This allows the battery to operate continuously within biological environments without relying on toxic or unstable electrolytes.”
The new battery features a composite gel electrolyte made of poly(L-lactide-co-ε-caprolactone) (PLCL) reinforced with a gelatin methacryloyl (GelMA) layer. The PLCL provides mechanical strength and flexibility, while the GelMA modification ensures strong interfacial adhesion with the electrode and facilitates efficient ion transport. This biocompatible configuration prevents oxygen and moisture from corroding the zinc anode—one of the key limitations of traditional metal–oxygen batteries. As a result, the battery maintains low polarization and stable electrochemical performance in both in vitro and in vivo environments.
In laboratory tests, the battery components exhibited excellent biocompatibility with negligible cytotoxicity. In animal experiments, histopathological and hematological analyses confirmed no signs of inflammation or organ damage, verifying its biosafety during continuous operation. Interestingly, the researchers observed capillary regeneration around the cathode, which naturally replenished oxygen to the device and helped sustain power output over time.
When implanted in rats, the soft-packaged Zn–O2 battery produced a power density of 1.96 μW/cm² at 0.98 V, sufficient to drive an integrated hydrogel-based mechanical sensor that continuously monitored cardiac signals. Further analysis revealed a two-electron oxygen reduction pathway in blood, providing new insights into the electrochemical behavior of oxygen in physiological fluids. Together, these findings establish a foundation for developing long-lasting and self-sufficient implantable power systems.
Beyond supplying energy, the new Zn–O2 battery represents a versatile platform for bio-interactive technologies. Because it consumes oxygen and releases mild electrical stimulation, it may be adapted for therapeutic purposes such as oxygen-depleting tumor treatment, wound healing enhancement, or localized drug release. Such multifunctional applications could integrate power generation with active medical intervention—an exciting direction for future bioelectronic devices.
“Our goal is to make implantable devices truly autonomous,” says Xizheng Liu. “By combining biocompatibility, corrosion resistance, and stable electrochemical output, this Zn–O2 system brings us closer to implantable technologies that can function safely for months or even years inside the body.”
Next, the team plans to further optimize electrode materials and architecture to boost energy density and extend operational life. They are also exploring ways to integrate the Zn–O2 battery with miniaturized sensors and stimulators, creating all-in-one self-powered implants that could transform personalized medicine and long-term health monitoring.
This work opens new possibilities for bio-compatible, oxygen-driven energy systems, offering a sustainable and safe power solution for the rapidly growing field of implantable medical electronics.
Other contributors include Jiucong Liu, Qingxu Zhang, and Pingli Wu from the Key Laboratory of Flexible Optoelectronic Materials and Technology (Ministry of Education), School of Optoelectronic Materials & Technology, Jianghan University in Wuhan, China, and Ling Zhang from the College of Chemistry and Materials Science, Hebei University in Baoding, China, Huiqiao Li from Huazhong University of Science and Technology.
This work was financially supported by the National Natural Science Foundation of China (22179095), and the Graduate Scientific Research Foundation of Jianghan University (KYCXJJ202423).
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.