According to foreign media, scientists are developing "transparent flexible batteries"

DGIST announced on April 23 that the team of Changsoon Choi, a senior researcher in the Smart Textiles Research Group, has developed a multifunctional transparent battery device based on thin-film graphene. This is a transparent battery that can both generate and store electricity and may be widely used in electronic products and electronic devices that can be attached to the skin.

Senior researcher Changsoon Choi's team actively uses "single-layer graphene film" as an electrode to develop transparent devices. Due to its excellent conductivity and thinness, single-layer graphene film is very suitable for electronic products that require batteries. The research team successfully improved the transparency of the battery (up to 77.4%) by using a polymer nanomat containing a semi-solid electrolyte, and the landscape and text can be clearly seen through the battery. In addition, the research team also designed a self-charging and storage structure for the battery device. This structure is to insert the energy storage plate into the upper layer of the power device and the energy conversion plate into the lower layer of the power device. Not only that, they even succeeded in making electronic products with a touch sensing system, which is to add a touch sensor just below the energy storage panel on the upper layer.

Changsoon Choi, a senior researcher in the smart textile research group, said, "We decided to start this research because we were amazed by the transparent smartphones that appeared in the movies. Although commercialization is still a long way off due to high production costs, we will do our best to advance this technology further because we were able to achieve remarkable results in the field of transparent energy storage, which has no research results."

Compared with traditional opaque lithium-ion batteries, the capacity of transparent batteries is still insufficient - it can only reach a pitiful 10 watt-hours per liter, which is about 1/10 of traditional lithium-ion batteries. However, the theoretical capacity of this new type of battery is the same as that of traditional batteries. The researchers believe that both the PDMS substrate and the electrode can be made thinner to increase the energy storage density, or electrode materials such as dwarf lithium cobalt oxide can be used to increase the battery capacity to 50 watt-hours per liter.

As for the application of transparent batteries, many companies have started to make transparent mobile phones as early as 2013. It is reported that in January 2013, Taiwan's Baochuang Technology demonstrated its latest development of the world's first fully transparent smartphone. The company spent 6 years and 10 million New Taiwan dollars to develop and design a transparent mobile phone by Taiwanese engineers. The entire body of the phone has no wiring, just like a piece of glass. This device of Baochuang Technology does not have an operating system yet, it is a pure hardware.

This transparent phone is designed to be drop-proof and lightweight, with a thickness of about 0.5 cm. Compared with the iPhone 5, it has a 4.3-inch screen and is 25% lighter. It has a single-sided touch screen but can display on both sides. LG has also launched transparent phones in the past, but only the buttons were transparent.

I believe that many consumers are still looking forward to transparent phones. However, although materials such as batteries and screens can be made transparent, there are still many obstacles on the road to transparent phones. For example, accessories such as mobile phone cards and memory cards must be inserted into the phone. However, virtual mobile phone cards will not be a problem in the future, but if you want to use transparent phones, it still requires accessory manufacturers in the supply chain to make significant innovations.