New 3-D design for mobile microbatteries

October 11, 2016, CNRS

In the race towards miniaturization, a French-US team—mostly involving researchers from the CNRS, Université de Lille, Université de Nantes and Argonne National Laboratory (US) as part of the Research Network on Electrochemical Energy Storage (RS2E)1-has succeeded in improving the energy density of a rechargeable battery without increasing its size (limited to a few square millimeters in mobile sensors). This feat was achieved by developing a 3-D structure made of microtubes, the first step towards producing a complete microbattery. The first experiments have demonstrated the excellent conductivity of the battery's solid electrolyte, whose highly encouraging performance is published in the journal Advanced Energy Materials on October 11, 2016.

In the era of connected devices, intelligent connected microsensors require miniature embedded energy sources with great energy density. For ultra-thin-or planar-microbatteries, increased means using thicker layers of materials, which has obvious limitations. A second method—used by the authors of the publication—consists in machining a silicon wafer2 and producing an original 3-D structure made of simple or double microtubes. 3-D batteries keep their 1mm2 footprint area, but develop a specific area of 50 mm2—an enhancement factor of 50! These robust microtubes are large enough (of the order of the micron) to be coated with multiple layers of functional materials3.

The main technological challenge consisted precisely in depositing the different materials that make up the in thin and regular layers on these complex 3-D structures. Using the of Atomic Layer Deposition (ALD), the materials perfectly took on the 3-D shape of the template without blocking the tube structures. In this way the researchers created an insulating thin film, a current collector, a negative electrode, and a solid electrolyte. The various analyses and characterizations (synchrotron X-ray nanotomography and transmission electron microscopy4) show that the successive layers are of excellent quality, showing conformality of nearly 100%. The interfaces are clean (no interdiffusion between the different chemical elements), with no pinholes, cracks, or fissures detected.

Lithium phosphate, the electrolyte of this future 3-D microbattery, is in solid form5. After depositing it using the same ALD technology, researchers showed that it has a high electrochemical stability window (4.2 V), high ionic conductivity, and low thickness (10 to 50 nm), which generates low surface resistance, all of which are very encouraging for the future performance of the 3-D battery.

The next step will consist in using ALD to develop thin films of positive electrode materials in order to create the first functional 3-D prototypes, which will certainly offer much greater performance than today's planar microbatteries.

Explore further: Garnet-type fast ionic conductor for all-solid-state lithium battery

More information: Atomic Layer Deposition of Functional Layers for on Chip 3D Li-Ion All Solid State Microbattery. Adv. Energy Mater.. doi: 10.1002/aenm.201601402

Related Stories

Solid batteries improve safety

August 16, 2016

Researchers at ETH Zurich have developed a lithium-ion battery made entirely of solid material: it contains neither liquids nor gels. The battery cannot ignite, even at very high temperatures, giving it a safety advantage ...

Melting, coating, and all-solid-state lithium batteries

January 1, 2016

The joint research team of Prof. Yoon Seok Jung (UNIST, School of Energy and Chemical Engineering) and Prof. Seng M. Oh (Seoul National University) discovered a new way to develop all-solid-state lithium batteries without ...

"High-occupancy" vehicle (HOV) battery

August 17, 2016

In lithium-ion batteries, a singly charged lithium atom (or "ion") flows between two electrodes while one electron is contributed to the electrical current in the external circuit. If too many lithium ions are intercalated ...

Recommended for you

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

The powerful meteor that no one saw (except satellites)

March 19, 2019

At precisely 11:48 am on December 18, 2018, a large space rock heading straight for Earth at a speed of 19 miles per second exploded into a vast ball of fire as it entered the atmosphere, 15.9 miles above the Bering Sea.

Levitating objects with light

March 19, 2019

Researchers at Caltech have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects' surfaces.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.