Came across a very educational thread on intentional failure of large RC lithium batteries and containment that can be applied to smartphones and tablets. I know I need to revise the way I charge my devices since they're sitting near a pile of paperwork on my desk. http://yuneecpilots.com/threads/lipo-bags.2365/ Also, video of RC battery spontaneously catching fire while not being used or charged. Aside from keeping it outdoors or in the fireplace there's not much you can do to contain the smoke. Make sure smoke alarms are near and functional if kept indoors. There's potential for fire so consider storing it in a fireproof bag or have one nearby to toss into. There's potential for scorching of the surface it's sitting on even in a fireproof bag so consider placement on concrete or stone tile floor, granite counter top, etc. Avoid stacking batteries/devices so they don't cause a chain or combined effect and over-pressure. Seems one of the more effective approaches to containment is storing in a fireproof bag then inside an enclosed genuine military surplus ammo can with seal removed and/or holes drilled in the top to vent pressure. Fireproof Bag https://www.amazon.com/BODAJING-Battery-Fireproof-20x11x15cm-Helicopter/dp/B01EX45NBY Fireproof Sleeve https://www.amazon.com/Generic-CoBean-Silver-Battery-Storage/dp/B005HTH78W Genuine military surplus ammo cans preferably .50 caliber can be found fairly cheap on Craigslist or at military surplus stores. Remove the seal and/or drill holes in the top to vent pressure.