Gary W. Rubloff, Sang Bok Lee, and coworkers at the University of Maryland have devised a precisely controlled fabrication method to make a battery that actually consists of billions of nanobatteries connected in parallel (Nat. Nanotechnol. 2014, DOI: 10.1038/nnano.2014.247). Each individual nanobattery is made inside a nanopore of a ceramic template by atomic layer deposition of ruthenium charge collectors topped with vanadium oxide storage material. Pristine V2O5 at one end serves as the cathode, and lithiated V2O5 at the other end serves as the anode. The battery array achieves the predicted capacity for the V2O5 storage material and power levels that are 10-fold higher than previously reported nanostructured batteries, the researchers say. More than 80% of the initial capacity is retained after 1,000 charge-discharge cycles. The controlled geometry allows investigation of ion transport between electrodes less than 100 nm apart, comments Christopher P. Rhodes, a nanomaterials expert at Texas State University. “This is an important and largely unexplored area of research,” Rhodes says.