Soft robots excel at flexing and handling delicate objects, allowing them to navigate tight or fragile environments to grow coral larvae in labs or inspect chemical plant piping. Yet it is still difficult to achieve true embodied intelligence in these robots, where sensing, actuation, and power all function together without external tethering.
Magnetic Fields Boost Soft Robot Batteries
Flexible materials can bend and adjust to their surroundings, but their power sources cannot. Traditional batteries tend to rigidify a soft robot’s structure, run out of energy quickly, or deteriorate when stretched, which keeps these robots tethered or short-lived.
Assistant Professor Wu Changsheng and his team from the National University of Singapore’s Departments of Materials Science and Engineering, and Electrical and Computer Engineering, have converted this drawback into a strength. In a study published in Science Advances, they show that the same magnetic fields used to maneuver soft robots can also boost the performance of the onboard batteries.
“Magnetic fields are usually applied to drive movement in soft robots—known as actuation—but we discovered they can also stabilize the electrochemical processes inside flexible batteries,” Asst Prof Wu said. “By letting actuation and energy management rely on the same physical principle, we can make the robot genuinely self-sufficient and efficient.”
Vertically Stacked Batteries Mimic Manta Ray Efficiency
The researchers created bendable zinc–manganese dioxide (Zn–MnO₂) batteries encased in soft silicone and arranged them in a vertical stack inside a manta ray–inspired robot. Crucially, this upright configuration—rather than the usual side-by-side layout—saves space and preserves the robot’s flexibility.
“We drew inspiration from the manta ray because its body naturally integrates movement, sensing, and energy use in the way we aim to replicate,” Asst Prof Wu explained. “Its anatomy enables coordinated multifunctionality in a compact, efficient form—an ideal biological template for embodied intelligence.”
Experiments showed that the magnetic field generated by the robot’s own ferromagnetic actuators helped stabilize the batteries’ internal electrochemistry, lowering the chance of dendrite formation—needle-like metal structures that can trigger short circuits—and preserving power output even after repeated deformation. With magnetic enhancement, the batteries kept 57.3% of their capacity after 200 cycles, nearly twice that of batteries without the magnetic boost.
“Further analysis revealed the mechanism behind this improvement. The magnetic field produces a Lorentz force on the moving ions in the electrolyte, altering the paths of zinc ions during plating. This creates a more uniform ion flow, encouraging even zinc deposition on the anode and effectively preventing dendrite growth.”
“At the same time, the magnetic field oriented the electron spins in the manganese oxide lattice, strengthening atomic bonds and protecting the crystal structure from breaking down during charging and discharging,” said Xiao Xiao, a Ph.D. student in Dr. Wu’s group and a co–first author of the study.
“This combined magneto-electrochemical stabilization, achieved in a completely flexible design, marks a promising advance toward long-lasting onboard power systems for soft robots working in demanding, ever-changing conditions.”
Intelligence Built Into The Body
To showcase the idea, the researchers created a magnetically driven manta ray robot that incorporates flexible batteries, soft magnetic-elastomer actuators, and a lightweight hybrid sensing and wireless-communication circuit. Its fins move in response to magnetic fields produced by an external coil or array of electromagnets, allowing the robot to maintain stable movement and adjust to varying water conditions.
As anticipated, the magnetic fields used to propel and guide the robot also help stabilize its energy supply—validating the team’s goal of integrating motion control with power regulation. The robot can carry out fundamental swimming actions, including straight-line movement, sharp 90-degree turns, and more intricate paths, all while sending real-time data to a computer that renders its behavior in a digital-twin model.
In this framework, the robot demonstrated autonomous responses. When it approached an obstacle, its onboard inertial sensors registered abrupt shifts in acceleration, triggering the control system to reorient and choose an alternate route. It effectively maneuvered through tight spaces by adjusting its posture and performed U-turns when it encountered barriers it could not bypass.
Integrated Systems Enable Stable, Responsive Movement
During disturbance tests, the feedback controller quickly corrected shifts in yaw, pitch, and roll caused by waves or contact, keeping its course steady. Built-in temperature sensors also allowed it to monitor the environment, producing maps of thermal variations in aquatic settings.
“By embedding actuation, sensing, and power systems throughout the robot’s structure, we can optimize its functional surface area while maintaining its softness,” explained Asst. Prof. Wu. “This approach allows the robot to move, sense, and react to its surroundings instantly.”
Looking forward, the team aims to broaden the robot’s sensing abilities by integrating compact sensors, such as ultrasonics for environmental awareness or chemical sensors for monitoring water quality. They are also investigating how magnetic enhancement could benefit other battery types, like lithium-ion, or alternative forms, such as wearable battery fibers, to boost energy density and extend operational time.
“Our goal is to create soft robots capable of autonomous thought and action in challenging or hard-to-reach environments—whether inspecting pipelines, observing marine ecosystems, or assisting in surgical procedures,” said Asst. Prof. Wu.
“By thinking creatively and critically about how energy and intelligence are embedded in the body, we can bring soft robotics closer to the elegance of nature—much like the fluid, majestic movements of a manta ray.”
Asst. Prof. Wu conducted this research in partnership with teams from Tsinghua University, the University of California, Los Angeles (UCLA), and Dartmouth College.
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