Researchers from Shenzhen University and Tsinghua University have published a comprehensive review of conformal 3D printing for shape-conformal batteries, highlighting its potential to revolutionize energy storage in flexible electronics, wearables, and compact embedded systems. Published in Virtual and Physical Prototyping in February 2025, the paper identifies key strategies, technological developments, and challenges in fabricating batteries directly onto curved surfaces, a critical step toward monolithic device integration.
Shape-conformal batteries
Traditional batteries, rigid, planar, and encased, pose limitations for emerging products that prioritize compactness and complex geometries. In applications like smart glasses, hearing aids, and miniaturized drones, available space often defines performance. Shape-conformal batteries promise to address this constraint by embedding power systems directly into structural components. However, conventional manufacturing techniques struggle with the deposition and assembly of battery materials on irregular surfaces. That’s where conformal 3D printing comes in.
Unlike flexible batteries, which are manufactured flat and bent into shape, conformal batteries are built layer-by-layer onto nonplanar geometries. This allows them to fully conform to the substrate, minimizing wasted space and improving integration. Technologies such as direct ink writing (DIW) and aerosol jet printing (AJP) have emerged as key enablers, offering high precision and multi-material compatibility for complex surfaces.
Recent developments in conformal battery fabrication
One notable example is the work by Yu et al., who used AJP to fabricate lithium-ion batteries on spherical surfaces. The aerosolized inks enabled non-contact deposition of both cathode and anode materials, which were printed directly onto a custom housing. The device, sealed with FDM-printed enclosures, achieved a discharge capacity of 135 mAh g⁻¹ at 0.1C and maintained 78.4% capacity after 30 cycles. While slightly lower than planar benchmarks, the results confirmed the viability of printing batteries directly on complex geometries.
Ahn et al. demonstrated the fabrication of ear-shaped zinc-ion batteries using a three-axis DIW system. MnO₂ and Zn electrodes were printed in interdigitated patterns, followed by a gel electrolyte and UV-cured resin encapsulation. In contrast to attempts at pressing flexible sheet-type batteries onto curved surfaces, where delamination and cracking occurred, the directly printed device achieved robust adhesion and electrochemical stability. It was able to power a hearing aid module, delivering 248 mAh g⁻¹ at 0.2 A g⁻¹.
Fassler et al. explored a hybrid technique, combining DIW and AJP to build a conformal lithium-ion battery on a square copper bar. The anode was deposited using DIW to allow high material loading, while AJP was used to achieve a thin, uniform separator layer (Pyrolux) between 4–12 μm thick. Although the final battery underperformed slightly due to challenges in vacuum sealing on the nonplanar surface, the study demonstrated a viable multi-material workflow.
In a more integrated demonstration, Meng et al. developed a five-axis printing platform capable of building batteries, circuits, and sensors in a single operation. Their system used multiple piezoelectric nozzles to deposit both low-viscosity materials (like silver ink) and high-viscosity battery pastes. A Zn-ion battery, temperature sensor, and LED were printed onto a curved substrate with UV-curing and sintering performed in situ. The final assembly functioned as a self-contained smart system, responding to heat and activating the LED.
Remaining barriers and future outlook
These studies reflect the growing sophistication of conformal battery research but also underscore persistent challenges. High-resolution printing of solid electrolytes remains difficult, particularly given the need to balance flowability, structural stability, and ionic conductivity. Packaging is another open issue, as traditional battery cases are incompatible with complex geometries. Some researchers have turned to UV-curable encapsulants, though long-term durability is still being evaluated.
Design software also remains underdeveloped. While slicing tools for flat printing are now mature, conformal battery printing requires custom algorithms for path generation on curved surfaces. Some research teams have built tools in Grasshopper and MATLAB, but user-friendly, commercial-grade solutions are scarce.
Despite these challenges, the authors argue that conformal battery technology is steadily advancing. As fabrication systems become more accessible and materials continue to improve, shape-conformal batteries may become a central feature of integrated electronic design. With further development, batteries could shift from standalone components to embedded systems that match the geometry, and function, of the devices they power.
Expanding the role of 3D printing in energy and electronics
This review builds on a growing body of research exploring how 3D printing can reshape energy storage and functional electronics. Recently reported by 3D Printing Industry, researchers at Seoul National University have demonstrated how additive manufacturing enables bioinspired energy systems for generation, conversion, and storage, pointing to a future where structural integration and performance go hand in hand. Meanwhile, advances in 3D printed electronics, such as those from nScrypt, highlight the increasing sophistication of conformal 3D printed circuit structures.
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Featured image shows conformal structural electrode strategy. Image via Liu et al., Virtual and Physical Prototyping.
