Don’t Buy Another Mobile Charger Until You Read This

Here’s a not-so-hot take: A mobile charger is a must-have travel accessory, one that belongs in every carry-on bag. Because, let’s face it, a dead phone while you’re trying to navigate unfamiliar streets or hail a rideshare service? Not fun.

These things have been around forever. Based on lithium-ion technology, they come in lots of shapes and sizes, with varying price tags and capacities. And they have one unfortunate problem: They’re dangerous. They’ve been known to burst into flame. (Wish I was making that up; I’m not.)

Fortunately, there’s a new battery technology in town, and it promises much safer mobile charging. It’s called semi-solid-state, and it offers several advantages over lithium ion — starting with that whole flammability thing.

See, li-ion batteries rely on a liquid electrolyte, which is subject to “thermal runaway”: It can overheat and catch fire. Solid-state batteries replace most or all of that liquid with a thick gel, which is much safer. (In some circles, these are referred to as “dry” batteries, even though that’s not exactly accurate.) Thus, the fire risk is greatly reduced; some manufacturers of these newer power banks even claim they “won’t catch fire,” full stop.

Other solid-state benefits include faster charging, greater capacity in the same form-factor, and as much as twice the longevity of their lithium-ion counterparts. Not all of those benefits have been realized in the first generation of power banks, but they’re off to a good start.

Speaking of which, you can already buy a solid-state mobile charger (and you should, because safety!), though I do have a couple caveats:

• You’re likely to pay 2-3x more than you would for a lithium-ion battery of the same capacity. Alas, new tech tends to sell at a premium.
• Many of the products below are MagSafe chargers, meaning they were designed with iPhones in mind. However, many Android phones can use these as well, and as long as there’s at least one USB-C port (which there always is), you can charger just about any other device as well.
• Even though they’re extremely unlikely to catch fire, these batteries can run warm or even hot, same as any other. Users often expect them to be cooler.

Below I’ve spotlighted what I consider the best solid-state mobile chargers you can buy right now.

Best semi-solid-state power bank overall

Ku Xiu S3

Capacity: 10,000 mAh

Wireless charging: MagSafe, Qi2.2, up to 25W

Thickness: 0.87 inch

Special features: LED status display, built-in stand, built-in USB-C cable

Price: $62.99

This is the current Cadillac of semi-solid-state power banks, with the fastest available wireless charging, several useful extras, and double the capacity of many competing products. And it’s priced only a few dollars higher than most of them.

Best budget semi-solid-state power bank

Meiyulin M10K

Capacity: 10,000 mAh

Wireless charging: MagSafe, up to 15W

Thickness: 0.59 inch

Special features: None

Price: $39.99

If you don’t mind a no-brand battery, this is one of the most affordable I’ve found. It’s just a basic-looking black brick (though there’s also a gold version) with a generous 10,000-mAh capacity. Because it doesn’t specify a Qi certification, however, and lists only compatible iPhone models, it may not be able to wirelessly charge Android phones.

Thinnest semi-solid-state power bank

BMX Air

Capacity: 5,000 mAh

Wireless charging: MagSafe, Qi2, up to 15W

Thickness: 0.26 inch

Special features: None

Price: $59.99

If you don’t want a bulky brick hanging off the back of your phone (or bulging in your pocket), this is the one to pick. It’s just 6.8mm thick, a svelte customer by any standards. BMX offers it in gold, silver, and black.