In the attached Mashable video from or about Jan. 4, 2014 Lauren Gores reveals that DARPA is working on a very special piece of electronics. In their work with SRI International and Honeywell the first utterly new device will be a vanishing silicon-air battery. Ms. Gores is careful to explain that the new device is intended to vanish and not explode. The funding for the research (and development) of this new technology/device is "$4.7 million". That may seem low but it is quite a lot for a '4th quadrant' type of technology - one that does not yet exist.
The SRI International current location for the work is at their headquarters in Menlo Park, California. It will be of local interest to see if any of this VAPR (Vanishing Programmable Resources program) work will be transferred to the SRI International location in Ann Arbor, Michigan. Battlefield electronics are a valuable resource - both to our military and others. Hitting a dissolve button would eliminate all field-deployed VAPR electronics and mix them with thin air. Is this environmentally friendly technology? The proposed batteries and electronics are also intended for field medical implants that resorb into the body. Will they both have the same "safe" chemical signatures?
Actually, DARPA's Microsystems Technology Office made a (humorous) announcement for their proposal on Jan. 28, 2013 - "This Web Feature Will Disappear in 5 Seconds". Here one finds that the medical version of the vanishing electronics are also meant to fight infections - that still does not imply the devices will be completely safe. Alicia Jackson (MTO program manager) did state that the devices may also decompose under environmental conditions as well.
The safety question is addressed in the report "The Rechargeability of Silicon-Air Batteries" by Professor Yair Ein-Eli, Technion Research and Development Foundation. On page 5 of his report Professor Ein-Eli states that the recent development of silicon-air batteries use silicon as the anode. That means "no safety issues" and the silicon reaction products with oxygen are "safe and environmentally friendly". A moisture barrier is needed, however, to protect the cell from the atmosphere and moisture. Should one conclude that the chemical nature of said barrier be key to making a military-grade battery that vanishes when the barrier is altered? It may be just a neat "chemical shift" in the battery or device that exposes it to environmental elements and then vanishes.