New nanowire technology offers hope for safer phone batteries

Nanowire-based fire-resistant paper developed by local researchers is expected to provide safer lithium-ion batteries.

Battery safety has become — literally — a hot topic in recent years, with several high-profile mobile phone battery explosions hitting the headlines, leading to a recall of about 2.5 million Samsung Galaxy Note 7 smartphones and eventually ending production of the model.

The Shanghai technical breakthrough will enable batteries to operate under much higher temperatures, researchers involved said.

Lithium-ion batteries are widely used in electronic products such as mobile phones, laptops and cameras. In most commercial lithium-ion batteries, separators, which are put between two electrodes to prevent short-circuiting, are usually made of polyolefin material.

The organic material is cheap and has a high electrochemical stability, but shrinks significantly or even melts when working at high temperatures, which could and has caused short-circuiting, fire and explosion.

“In our experiments, a new kind of nanowire-based separators showed advantages not only including high flexibility, better battery performance, but also good thermal stability and fire-resistant properties,” said Professor Zhu Yingjie, from Shanghai Institute of Ceramics at the Chinese Academy of Sciences.

The latest application on separators is co-developed by research teams led by Zhu and Professor Hu Xianluo from Huazhong University of Science and Technology.

The development follows on from that of a fire-resistant paper based on hydroxyapatite nanowires, which was developed by Zhu’s research team earlier.

Zhu said their new kind of separators can maintain the material’s structure at a temperature as high as 700 degrees Celsius.

An ordinary lithium-ion battery usually works below temperatures of about 60 degrees Celsius, Zhu added. But with the new separators, the batteries used in phones can operate at 150 degrees.

There are already firms showing an interest in the battery application of the nanowires-based separators and to commercialize the new technology with the research teams, said Zhu.