The whole trend toward custom Lithium-ion battery packs seems to be driven by making devices thinner--not just phones, tablets, and laptops, but everything. The

The whole trend toward custom Lithium-ion battery packs seems to be driven by making devices thinner--not just phones, tablets, and laptops, but everything. They then integrate a USB, micro-USB, or even USB-C charger. Rechargeable is nice...replaceable is nice. But rechargeable and replaceable? I hope that we get back on a trend to use standard batteries, like AAAs, which have many excellent rechargeable Lithium-ion options now. I have plenty of AA/AAA-powered devices and about a dozen or so rechargeable AAA's cycling in and out. For some reason rechargeable 9-volt batteries haven't really caught on. They seem to have weak capacity and are expensive.