Micro-capacitor breakthrough

Chinese scientists have constructed a prototype of planar sodium-ion microcapacitors with high power density, superior thermal stability and excellent mechanical flexibility.

The prototype was co-developed by two research groups led by Wu Zhongshuai from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, and Bao Xinhe, a CAS academic and president of the University of Science and Technology of China.

By coupling with a battery-type urchin-like sodium titanate anode and a capacitor-type nanoporous activated graphene cathode, the as-fabricated all-solid-state NIMCs working at 3.5 volts exhibited high volumetric energy density and an ultralow self-discharge rate, according to the researchers.

Micro-capacitors and micro-batteries have been acknowledged as key power sources for miniaturized smart and integrated electronics, such as remote sensors, micro-robots and self-powered micro-systems.

The NIMCs assembled by DICP scientists would enjoy abundant sodium resources, low cost and electrochemical properties of sodium compared with lithium. While showing great potential for making flexible micro-electronic devices, lithium’s massive applications will likely be snuffed out by limited supply and rising cost.

The micro-supercapacitors with multi-directional ion diffusion pathways and better capacitance and rate capability, hold great potential.