Researchers eye solid-state batteries

The relatively long life of lithium ion batteries makes them the rechargeable choice for a wide range of devices. Nevertheless, lithium ion batteries rely on liquid chemistries involving lithium salts dissolved in organic solvents, creating flame risks that would be avoided if the cells were completely solid-state.

Recently, a team of researchers at Tohoku University in Japan managed to create a new type of lithium ion conductor that could serve as the basis for an entirely new generation of solid-state batteries.

Essentially, the connector uses rock salt Lithium Borohydride (LiBH4), a well-known agent in organic chemistry laboratories that has been considered for batteries before, but up to now has only worked at high temperatures or pressures.

In the journal APL Materials, the researchers describe how they doped a cubic lattice of KI molecules with the LiBH4. This allowed the team to stabilize the high-pressure form of Lithium borohydride, effectively creating a solid solution at normal atmospheric pressure that was stable at room temperature.

During the process, the team made the peculiar discovery that the Li+ ions functioned like pure Li+ ion conductors, even though they were just doping the KI lattices. This is the reverse of the normal doping technique, in which a small amount of stabilizing element would be added to an ionic conductor abundant in Lithium.

“In other words, LiBH4 is a sort of ‘parasite’ but not a host material,” explained Hitoshi Takamura who led the research at Tohoku University. 

He and his colleagues have dubbed this mechanism “parasitic conduction,” suggesting that it could be broadly applied in the search for new batteries – anywhere that small amounts of Li+ ions could be used to dope an oxide, sulfide, halide or nitride host material.

“This work suggests the potential of this mechanism in the ongoing search for the perfect material for use in solid state batteries. The urgency of this quest has been abundantly clear after the grounding of so many aircraft in recent months,” Takamura added.

3D printed bone transplants a success in Japan

3D printing technology is fast becoming mainstream in the medical world. Indeed, earlier this summer, researchers managed to design and print a 3D splint that saved the life of an infant born with severe tracheobronchomalacia – a serious birth defect that causes the airway to collapse. Melbourne scientists also took a big step towards the development of “grow your own” cartilage to treat cancers, osteoarthritis and traumatic injuries using 3D tech, while 3D printed orthopedic implants were successfully fitted in Peking’s University Third Hospital in Beijing.

And now doctors at the Kyoto University Graduate School of Medicine in Japan have successfully transplanted 3D printed bones into four patients with cervical spine (cervical) disc herniation. Following the transplants, symptoms such as gait disturbance and hand numbness improved.

The cost of making such artificial bones is only several thousand yen (1000 yen = 10 US dollars).

“Based on images of MRI and CT scan of patient’s neck, researchers sent the design file to a 3D printer,” a 3DERs.org writer explained. “Composed by thin layers of titanium powder the 3D printed bone fit perfectly to the cervical spine. After an extra chemical and heat treatment the 3D printed bone was transplanted into the patient’s neck.”

The cost of making such artificial bones, including part of a skull, femur and spine? Only several thousand yen per bone (1,000 yen = 10 US dollars).

As previously discussed on Bits & Pieces, the Maker Movement has used Atmel-powered 3D printers like MakerBot and RepRap for quite some time now, but it is quite clear that 3D printing recently entered a new and important stage in the medical space.