The ever-increasing demand for portable power sources has motivated considerable research efforts towards a variety of power and energy systems.

Xiangfefng Duan, University of California, Loas Angeles, USA, and colleagues report a high capacity silicon–air battery using
nanostructured silicon and alkaline solution based electrolyte that only involves environmentally friendly elements such as silicon, potassium, oxygen, and hydrogen.

The silicon surface is first modified by the metal-assisted electroless chemical etching method. The assembled battery displays a flat and stable discharge curve with a voltage ranging from 0.9 to 1.2 V
under different discharge current densities over days. In contrast contrast, the unmodified silicon wafer becomes passivated quickly in the alkaline solution and therefore the potential drops rapidly after discharging for a short period of time (minutes).

• High-Capacity Silicon–Air Battery in Alkaline Solution,
  Xing Zhong, Hua Zhang, Yuan Liu, Jingwei Bai, Lei Liao, Yu Huang, Xiangfeng Duan,
  ChemSusChem 2011.
  DOI: 10.1002/cssc.201100426