Belkin's Semi Solid State Batteries Cut Weight in Half — Here's the Catch

Every gear reviewer talks about weight. Every traveler thinks about it. And every portable battery manufacturer has spent the last decade pretending lithium-ion was the final answer. Belkin just called that bluff with their new semi solid state battery lineup, and the results are genuinely surprising.

What semi solid state actually means

Traditional lithium-ion batteries use liquid electrolytes. Full solid state batteries — the holy grail everyone’s chasing — replace that liquid entirely with solid materials. Semi solid state sits in between: a gel-like electrolyte that’s more stable than liquid but easier to manufacture than pure solid state. Belkin’s implementation cuts weight by roughly 45% compared to their equivalent lithium-ion packs while maintaining similar physical dimensions.

The lineup and what you’re paying

Three models at launch: a 5,000mAh at $49, a 10,000mAh at $89, and a 20,000mAh at $149. For context, Belkin’s current lithium-ion 10,000mAh pack runs $39. You’re paying more than double for the weight savings. The 10,000mAh semi solid state weighs 118 grams — their lithium-ion equivalent hits 211 grams. That’s meaningful if you’re counting ounces.

Who this is actually for

Let’s be honest: most people don’t need this. If your battery lives in a backpack or desk drawer, the weight difference is irrelevant. But ultralight backpackers, bikepacking enthusiasts, and anyone who travels carry-on-only with a weight limit will feel the difference immediately. The 20,000mAh model at 226 grams competes with lithium-ion packs half its capacity.

The capacity-per-dollar problem

Here’s the catch nobody’s talking about yet: semi solid state batteries currently offer lower energy density per dollar spent. That $149 20,000mAh pack delivers the same juice as a $60 lithium-ion equivalent. You’re essentially paying $90 for weight reduction. Whether that’s worth it depends entirely on how much you value grams saved versus dollars spent.

Longevity might be the sleeper advantage

Belkin claims 1,500 charge cycles before hitting 80% capacity — roughly double what most lithium-ion packs deliver. If that holds up in real-world use, the cost equation shifts. A battery that lasts six years instead of three starts to make the premium look reasonable. I’ll need months of testing to verify those claims, but it’s worth watching.

My take on the timing

Semi solid state has been “coming soon” for years. Belkin shipping actual products you can buy signals the technology is finally mature enough for consumer pricing — even if that pricing remains steep. This first generation is for early adopters willing to pay the premium. The real story is what happens in 18 months when competition drives prices down and capacity up.

I’ll have hands-on testing of all three models next week. For now, if you’re the kind of person who weighs their toothbrush before a trip, Belkin just gave you a reason to pay attention.