"Solid-state" has become the most-used and least-defined phrase in drone battery marketing. Datasheets quote 350, 450, even 575 Wh/kg; product titles say one C-rating and spec tables another; and almost nobody explains what is inside the pouch. This guide sets out what the term means, why these cells store so much more energy than a 21700 pack, what they give up in return, and how to evaluate a supplier's claims before you commit a fleet to them. It is written by the people who build our solid-state packs, and it says so where the chemistry is not on our side.
What "Solid-State" Means — and What It Does Not
Every lithium-ion cell has three parts that matter here: a cathode, an anode, and the electrolyte through which lithium ions travel between them. In a conventional Li-ion cell — the Samsung 50S or Molicel P50B in our 21700 packs — the electrolyte is a liquid: lithium salt dissolved in organic carbonate solvents, soaked into a porous separator. In a LiPo the liquid is held in a polymer gel, but it is still a liquid-based system.
A true all-solid-state cell replaces that liquid with a solid ion conductor — a sulfide, oxide or solid polymer — with no liquid at all. Those cells exist in laboratories and in early automotive pilot lines. They are not, in 2026, available in volume in the formats and quantities a drone battery manufacturer can buy.
What is available, and what every "solid-state drone battery" on the market today is built from, is a semi-solid-state cell: a pouch cell in which most of the liquid electrolyte is replaced by a solid polymer or gel matrix, combined with a high-nickel cathode and a silicon-carbon composite anode. The electrolyte is immobilised rather than eliminated. That is a real and useful change — it improves thermal stability and allows the cell design choices that lift energy density — but it is not the all-solid cell of the headlines. Our packs are semi-solid-state, our pages say so, and the cell datasheet is available to any buyer who asks. Any supplier who will not tell you which of these two things they are selling should be asked why.
Why the Energy Density Is Higher
The semi-solid cells in our packs deliver 345–394 Wh/kg at pack level. A well-built 21700 pack manages about 230; a LiPo, 150–180. Four design choices account for the gap.
The anode is silicon-carbon rather than graphite. Silicon stores roughly ten times more lithium per gram than graphite; even a modest silicon fraction lifts capacity substantially. The 50S already uses a silicon additive, which is how it reaches 5000mAh in a 21700 can. Semi-solid cells push the silicon content much further, which is possible because the immobilised electrolyte and the pouch format tolerate the expansion of silicon during charge better than a cylindrical can does.
The cathode is high-nickel NCM and the cell charges to a higher voltage. Our cells terminate at 4.25 V per cell rather than the 4.20 V of standard Li-ion. The extra 50 mV per cell is worth around 8 % of capacity, and the high-nickel chemistry stores more lithium per gram than the cathodes in older cells.
The pouch format removes the steel can. A 21700 cell is roughly 10 % steel by weight, plus the internal current collectors and the empty volume at the ends of the jelly roll. A pouch cell is electrode, separator and a thin laminated foil, so almost all of the mass is active material. The trade is mechanical: a pouch has no structural protection of its own, which is why our packs ship in a hard-shell case rather than heat-shrink.
The semi-solid electrolyte allows thinner separators and closer electrode spacing without the short-circuit risk that a free liquid electrolyte would carry. Less inert material per Wh, again.
Add those four together and a 6S 22000mAh pack stores 502 Wh at 1,400 g — 358 Wh/kg on our scale, with case, harness and connector included.
Pack-Level vs Cell-Level Wh/kg: How to Read the Number
This is where most of the marketing confusion lives. A cell datasheet quotes energy density for the bare cell. A pack adds tabs, nickel or busbars, balance harness, discharge leads, connector, case, and often a small BMS. On a 21700 pack that overhead is 11–13 % of mass; on a cased pouch pack it is 10–15 %. So a cell rated at 400 Wh/kg becomes a pack at roughly 345–360 Wh/kg, and a 575 Wh/kg figure — which is a lithium-metal cell number, a different chemistry again — has no business on a lithium-ion product page.
The arithmetic is simple enough to check yourself: nominal voltage × rated Ah ÷ finished pack mass in kg. For our 6S 40000mAh pack that is 22.8 V × 40 Ah = 912 Wh, ÷ 2.35 kg = 388 Wh/kg. If a supplier's page gives you weight and capacity, run the sum. If the published Wh/kg is higher than the sum produces, the published number is a cell figure, or worse.
Two more things to check on the same page. First, whether the voltage quoted is nominal (3.8 V/cell for these cells, 3.6–3.7 V for standard Li-ion) or fully charged (4.25 V/cell) — quoting the charged voltage inflates Wh by about 12 %. Second, whether the mass is the bare cell stack or the shipped pack. We publish nominal voltage and shipped mass, because those are the numbers that determine how long your aircraft stays up.
What Solid-State Gives Up
Energy density is bought with other properties, and any honest comparison has to price them in.
Discharge current. Silicon-heavy anodes and immobilised electrolytes conduct ions less readily than a liquid system in a power cell. Our 11.5Ah pack is rated 6.5C continuous, the 22Ah 5C, the 40Ah 3C — with 10-second peaks of 100–200 A. A Molicel P50B pack runs 9C continuous and 12C peak. If your airframe pulls more than about 5C in cruise or hover, a semi-solid pack will sag, heat and age; that is a P50B mission. Our Molicel cell guide covers the high-current end of the range.
Charge rate and voltage. Charge at 1C, to 4.25 V/cell, with a LiHV or user-defined charger programme. Faster charging is not supported, and charging below 5 °C is not supported. Fleets that turn packs around in twenty minutes will need more packs in rotation.
Cycle life. High-silicon anodes expand and contract more than graphite on each cycle, and that mechanical stress is the main ageing mechanism. The datasheet rating is 500 cycles to 80 % capacity — on par with our 21700 packs, which is unusual for a silicon-heavy chemistry and one of the reasons we selected this cell. Shallower cycling and cool storage extend it; deep discharge and hot charging shorten it. Our lifespan and care guide applies with the numbers adjusted.
Temperature window. Charge 5–45 °C, discharge −20 to 55 °C. The low-temperature charge limit is stricter than a 21700 pack; for field charging in winter at altitude, see our cold weather guide.
Mechanical handling. Pouch cells swell slightly in normal use and must not be punctured, crushed or bent. Our packs are cased for that reason; do not strap a bare pouch pack to an airframe.
Price. Per Wh, our 6S semi-solid packs list at roughly ₹41–43 against ~₹31 for Samsung 50S and ~₹49 for Molicel P50B. Cheaper per Wh than the power cell, dearer than the energy cell — and the comparison that matters is cost per flight-hour, below.
The Flight-Time Maths
Take a mapping quadcopter with a 4.5 kg all-up weight that hovers at 850 W and cruises at 700 W, carrying a 1.4 kg battery. On a 21700 pack at 230 Wh/kg that is 322 Wh; on a semi-solid pack of the same mass, 502 Wh. Discharge to 20 % remaining and allow 5 % for losses, and the usable energy is 245 Wh and 381 Wh respectively. At a 720 W mission average, that is 20 minutes against 32 minutes — a 55 % gain in survey line per sortie from a pack of identical weight, with a current draw of 32 A that sits comfortably inside the semi-solid pack's 110 A continuous rating.
Now price it. If the semi-solid pack costs 40 % more per Wh and delivers 55 % more flight time per sortie, the cost per flight-hour of battery is already lower before cycle life is considered. Cycle life does not pull it back: at a rated 500 cycles to 80 % capacity the semi-solid pack matches our 21700 packs, so the flight-time gain carries straight through to cost per flight-hour. Work the sum for your fleet with the long-range and BVLOS energy-density guide as the template. For most cruise-dominated operations the flight-time gain wins, because pilot time, permit windows and airframe hours cost more than cells.
Where It Wins and Where It Does Not
| Mission | Typical draw | Verdict |
|---|---|---|
| Mapping and photogrammetry | 2–4C cruise | Solid-state — longest lines per sortie |
| BVLOS and long-range corridor | 2–4C cruise | Solid-state — endurance is the mission |
| VTOL fixed-wing | 8–12C transition, 1–3C cruise | Solid-state for cruise-dominated profiles; check transition current against the peak rating, or use a 21700 pack for the lift motors |
| Surveillance loiter | 3–5C hover | Solid-state on light payloads; Samsung 50S on heavier ones |
| Delivery and cargo | 4–6C loaded | Borderline — solid-state on the 40Ah packs (3C rating) only for light parcels; P50B for heavy |
| Agricultural spraying | 8–12C | Molicel P50B — not a solid-state mission |
| Heavy-lift, cinelifter, FPV | 10–25C | Molicel P50B or LiPo |
| Training fleets | 3–6C, many cycles | Samsung 50S — cycle life and price per Wh matter more than endurance |
How to Evaluate a Solid-State Supplier
Whether you buy from us or anyone else, ask for six things. The cell datasheet, with the manufacturer's name and model number — not a pack datasheet "released against RFQ". Pack-level Wh/kg with the mass it was calculated from, so you can run the sum. Continuous and peak discharge as separate figures, with the temperature condition attached to the peak. Cycle life with its test conditions: C-rate, depth of discharge and the capacity threshold. The charge and discharge temperature windows. And the UN 38.3 test summary, because without it the pack cannot legally travel by air. A supplier who can produce all six is selling a cell they understand; one who cannot is selling a word.
The Revogreen Solid-State Range
Our packs are built on semi-solid-state pouch cells in a hard-shell case with strap points, a potted balance harness, and XT90 or AS150U connectors sized to the pack's continuous current. Four families are listed: 22.8V 6S in 11500, 15000, 22000 and 40000mAh; 30.4V 8S in 15000 and 22000mAh; 45.6V 12S in 22000 and 40000mAh; and 53.2V 14S at 40000mAh. Every pack ships with a serial number and its own capacity test result.
As of publication the 6S 11500mAh is in stock. Cells for the remaining configurations arrive at our facility on 15 September 2026, and pre-orders placed now are built in order of receipt and dispatch by 22 September, with free cancellation before dispatch. Other voltages, capacities, connectors and BMS builds are available through our custom pack programme.
Frequently Asked Questions
Is a solid-state drone battery safer than LiPo? Safer in one specific way: the immobilised electrolyte is far less prone to leaking and to the fast, self-sustaining thermal runaway that liquid-electrolyte cells can suffer when punctured or overcharged. It is not immune — a high-nickel, high-silicon cell still stores a great deal of energy — and the pouch format needs mechanical protection. Follow the same storage, charging and transport practices as for any lithium pack.
Can I charge it with my existing charger? Yes, if the charger has a LiHV or user-defined programme that can be set to 4.25 V per cell and a 1C current limit. Charging to 4.20 V works but leaves about 8 % of capacity unused; charging above 4.25 V or above 1C shortens life and voids the warranty. Set the flight controller's cell-voltage alarms for a 3.8 V nominal chemistry — the sag curve differs from both LiPo and standard Li-ion.
Why is the C-rating lower than my Li-ion pack? Because the cell is optimised for energy per gram, not ion transport per second. Silicon-heavy anodes and a semi-solid electrolyte move lithium more slowly than a liquid-electrolyte power cell. Size the pack so your cruise or hover draw sits well under the continuous rating and use the peak only for climb and gusts.
Will a true all-solid-state drone battery arrive soon? Automotive pilot lines are producing sulfide and oxide all-solid cells in small volumes, and drone formats will follow, but not in the quantities or at the prices a fleet operator can plan around in 2026. When they do, we will list them as what they are.
Does the higher energy density mean a lighter drone? Either a lighter pack for the same endurance or, more usefully, the same pack mass for 50–60 % more endurance. Because hover power scales with all-up weight, trimming battery mass also reduces the power needed to carry it, so the gain compounds slightly in the lighter-pack case.
How should I store a semi-solid pack? At 40–60 % state of charge, 22.2–22.8 V on a 6S pack, in the case, between 10 and 25 °C. Do not store fully charged for more than a few days; high-nickel cathodes age fastest at high state of charge and high temperature.
Flight-time and performance figures in this article are illustrative planning estimates. Validate all figures on your specific airframe and payload before operational deployment.
The 6S 11500mAh pack is in stock now; every other configuration is open for pre-order, built in order of receipt and dispatched by 22 September — with free cancellation before dispatch. Need a different voltage, capacity or BMS? Ask about a custom build.
Shop & Pre-order Request a QuoteFlight-time and cost figures in this article are illustrative planning estimates calculated from pack-level specifications. Validate against your specific airframe and payload before operational deployment.
