How Close Are We to Solid-State Batteries?

If you've been following battery tech

for the past decade, you've heard the

solid state battery story before. Toyota

promised them by 2025. Samsung said they

were just around the corner.

QuantumCape's stock soared on promises

of a revolutionary battery. And yet

here we are still driving cars with the

same lithium-ion tech. And if the

sliding deadlines weren't enough of a

headache, the term solid state battery

has become a marketing buzzword and is

quickly losing meaning as a result. But

here's the thing. 2025 and 2026 might

actually look a little different.

Companies aren't just filing patents

anymore. They're opening factories.

They're putting innovative new batteries

in actual vehicles. Mercedes just drove

749 mi on a single charge with one. MG

is taking pre-orders for a car with a

semi-olid state battery for under

$15,000.

So, is this finally it? Are solid state

batteries, or at least their close

relatives, finally here, or we just

being sold another round of hype? I'm

Matt Ferrell. Welcome to Undecided.

This video is brought to you by Incogn.

Before we dive into who's shipping what

we need to address a credibility crisis.

Remember our investigation into

Yoshino's so-called solid state battery?

Well, when the company Tech Insights

cracked it open, they found liquid

electrolyte in both the anode and

cathode. So, was it not a solid state

battery? Well, yes and no. Solid state

battery has become kind of an umbrella

term. What you're probably picturing is

an all solid state battery or an ASSB

which means there's zero liquid.

However, there's also semisbs where less

than 10% of the electrolyte is liquid.

Less than 5% means it's a quasi SSB. The

catch, these definitions aren't

universally agreed upon. As

QuantumCape's Tim Holm told me, each

company has their own thresholds. Some

don't even base it on liquid content.

They base it on performance instead.

Have you ever been in the middle of

eating ice cream only to notice that

it's actually labeled as frozen dairy

dessert? It's a lot like that, except we

don't have a USDA equivalent for solid

state batteries. So, here's my take. I'm

not sure it matters that much. What

matters is the user experience. Does it

charge faster? Give you more range? Is

it safer? If a battery charges to 80% in

10 minutes and won't catch fire when

it's punctured, I don't care if it has

3% liquid electrolyte or zero. The terms

are becoming meaningless. And combined

with ever sliding deadlines, we've got a

real credibility crisis. Even if this

boom of prototypes and pilot factories

is real, commercialization still lies

beyond what experts call development

hell. ID Tech X's vice president for

research, who's Dr. James Edmonson, told

Forbes, "While progress is generally

being made, he thinks real

commercialization is still years away.

In terms of seeing them in larger

production volume vehicles, we wouldn't

expect that until early 2030s. Even by

2035, we are predicting just over 100

gatt hours of capacity for solidstate

batteries, compared with our prediction

for the overall EV car at around 3,800

gatt hours in the same year. At this

point, it's a necessity to be skeptical

about any and all SSB claims. So, let's

look at what's actually real, what's

close, and what's still just promises.

Let's start with what you can actually

get, your, hands, on,, or, at least, pre-order

right now. Well, depending on what part

of the world you're in, Chinese company

SIC Motor officially opened up pre-sales

for the allnew MG4 model this past

August. This makes it among the first

mass-produced vehicles to sport a

semi-olidate battery. And yes, it's a

semiolidate battery with a reported 5%

liquid electrolyte, not a full all

solidstate battery. SIC claims its

battery successfully passed safety

tests, including a three direction

needle penetration test without any

smoke. But it's also not stated, at

least not in English, if those are

in-house or third party tests. There's

not a lot of reporting about what the

exact stats of the battery are. But

based on information revealed during a

July media event, the semi-olidstate

battery will have a range of about 537

km or 333 mi and an energy density of

about 180 W hours per kilogram. That

said, I still haven't heard a peep about

how fast it charges. The MG4 has a

handful of versions, but it only looks

like the most expensive option, the

Anin, will include the semi-olid state

battery, and it will retail for the

pretty reasonable 102,800

yuan or about $14,290.

I don't want to overhype this in part

because the engine version hasn't

delivered yet, but it's nice to see that

at least, some, kind, of, solidstate, battery

techbased car making it to

commercialization's finish line. In the

case of this car, it sounds like this is

more about safety benefits. Then there's

Mercedes-Benz partner with Factorial

Energy. Factorial is a new face for the

channel. In 2023, the company opened an

SSB plant in Massachusetts. Its lineup

includes the FEST quasi solid state

battery and the Solstice all solidstate

battery. I can't find anything stating

if this plant will be producing the

Fest, the Solstice, or both. Though

keep in mind that the plant predates the

Solstice announcement. Mercedes just

completed a long-distance test with its

EQS model equipped with Factorial's

solidstate battery, and the result was

impressive. 749 mi on a single charge.

That's not a lab result under perfect

conditions. That's a real car on real

roads. Mercedes says the test EQS use

Factorials Solstice all solidstate

battery technology. These aren't

vaporware. They're functioning vehicles

proving the technology works outside

controlled lab environments, but they're

also not quite the revolutionary leap

the hype machine promised us for the

past decade. So, what about the

companies claiming they're just months

away from mass production? We'll dive

into the major automakers that have

opened up pilot plants with bold

promises in a moment. But first, while

we're talking about things that you can

actually control, let's talk about

controlling your personal data. Today's

sponsor, Incogn, can help you get to the

source of the problem and restore some

of your privacy. Data brokers collect

and sell your personal details to people

who might use it against you. We're

talking about some real threats like

identity theft, scams, and stalking

because they can't harm you if they

can't find you. Your home address, phone

number, and relatives information are

being sold online, and criminals use

this data to take out fraudulent loans

or track people down in real life. I

signed up for Incognal right to work on

my behalf, and then just sat back and

relaxed. It's really that easy. Their

custom removals feature is really cool.

You can flag any websites where your

data is exposed, and they'll get it

removed. I've seen a dramatic drop in

where my information is showing up

online. If you want to take back control

of who has your personal information

give Incogn try. Use code undecided at

the link below and get 60% off an annual

plan. Thanks to Incogn and to all of you

for supporting the channel. Now, back to

those pilot plants and their promises.

Now, let's look at who's getting very

close. Several major players have pilot

production lines running, which means

they're past the lab stage, but not yet

at mass production. Pilot plants are the

final gate before commercial production.

QuantumCape partnered with Volkswagen

Group to put its QSE5 solidstate battery

in the new Ducatti V21L electric racing

motorcycle. The QSE5 has a 844Wh per

liter energy density, charges from 10%

to 80% in around 12 minutes, and

Volkswagen says it's capable of race

level power outputs. The all-electric

V21L had 150 horsepower and hit 170 mph

on the Magello circuit. The QSC5s are

being produced via the Cobra separator

system, which we explored last year

which heat treats their batteries oxide

separator 25 times faster. I can't find

independent info on what subspecies of

Cellstate battery the QSC5 is, but what

matters is whether performance and

timelines match the promises.

QuantumCape initially aimed for

commercial production in 2024, and in

2025, they began shipping samples to

launch customers with field testing

starting in 2026. That's progress, but

field testing isn't commercial

production, and the timeline keeps

sliding a little bit. Next up is Solid

Power and BMW working on an all

solidstate battery for the new BMW i7.

Solid Power clearly states that this

battery is an all solid state battery.

The company has worked with BMW since

2016, and this particular solid state

battery is sulfidebased. The big

advantage, sulfide solidstate batteries

can be produced with industry standard

roll-to-roll manufacturing equipment.

This could be critical because finding

cost-effective ways to manufacture solid

state batteries at scale remains an

ongoing challenge. Solid Power claims it

can manufacture solid state batteries 15

to 35% cheaper than competitors.

However, BMW and Solid Power's own press

releases note that further development

steps are required. Not exactly

confidence inspiring, especially when

Solid Power was saying in 2020 that they

were hoping to sell batteries by 2021.

We've heard these optimistic timelines

before. While we're on solid power

let's talk about its partner SKON, one

of South Korea's powerful family-owned

conglomerates known as Cables. SKON has

its own all-state battery and claims it

can mass-produce it using warm isostatic

pressfree or WIP technology. This

technique reduces pocity and increases

density, suggesting SKON's solid state

batteries have a ceramic core, but

that's not clearly stated. WAP applies

uniform pressure to electrodes at

elevated temperatures improving energy

density and performance while minimizing

heat generation and the results an

energy density of 800 W hours per liter

which is twice what lithium ion nickel

manganese cobalt batteries offer.

However, cell sealing proved difficult

to automate so tapped solid power for

help. Things seem to be working out and

they opened a 50,000t pilot plant in

Dejon, South Korea in September and

moved their release date from 2030 to

2029. They actually moved it up.

Surprising given the history of sliding

deadlines, although 2029 is still 4

years away. Then there's Nissan claiming

it'll have all solidstate battery

vehicles by 2028. The company is

developing in-house batteries but

partnered with US-based LICAP for

cathode electrode production process

technology. The battery stats are

unclear. We can make some educated

guesses maybe by looking at LICAP's

numbers, but that's just a guess. Nissan

reached out to LICAP for its activated

dry electrode technology, which

manufactures electrodes without

solvents. Ordinarily, solvents melt

battery layers together for better

charge flow. But manufacturers have to

wait for electrodes to dry, then

recapture the solvents for reuse. Both

processes are timeconuming and

expensive. Nissan figures skipping these

steps will significantly reduce

manufacturing costs, but the company

only opened a pilot plant earlier this

year, so we'll be waiting a while to see

if that's true.

That's a lot of different approaches to

solidstate batteries coming down the

pipeline. Surely, one of them has to

make it, right? Well, before any of us

get too excited, let's talk about what

they're not telling you, because there

are serious manufacturing challenges at

play that could delay or even derail

these timelines. First off, temperature

sensitivity. Some solid electrolytes

only perform well at elevated

temperatures or suffer when it's humid

which isn't ideal in the real world. In

colder climates, this necessitates the

need for heavy energyintensive internal

heating systems. And these eat into the

energy savings, making the car heavier

which harms your range and drives up the

overall costs. This isn't a minor

inconvenience so much as a fundamental

challenge. It affects where and how

these batteries can be deployed. Plus, a

paper from Clemson University's

Department of Electrical and Computer

Engineering points out life cycle is

still an issue. This is where dendrites

come back into the picture again because

they get bigger every time a battery is

used. The solid state battery buzz makes

it sound like this is a solved problem.

As we've seen, there's a lot of

strategies for managing dendrites, but

there's still a concern. They can pierce

through a solid electrolyte just like

they do with a liquid one, causing

internal short circuits. Different

materials have their own way of handling

this, but no approach has completely

eliminated the problem. Less dramatic

but no less important is the solid

electrolyte interphase or SEI layer.

This is a metallic layer that builds up

around the electrodes with repeated use.

It simultaneously eats away at the

electrolyte to build itself while making

it harder for lithium ions to pass from

one electrode to the other. It usually

drops the battery's capacity and overall

just harms the performance. And much

like dendrites, there are ways to manage

this, but none of them are easy or

cheap. There's also the challenge of

maintaining good contact between the

solid electrolyte and the electrodes.

Unlike liquid electrolytes that flow and

maintain contact naturally, solid

materials can separate or develop gaps

during charging and discharging cycles.

This increases resistant and reduces

performance over time. Some companies

are using various pressing techniques or

composite materials to address this, but

it adds complexity and cost to

manufacturing. That's all before we get

into the difficulty of mass production.

Even if we solve all those challenges

and right now that's a big if, can we

implement them efficiently and cost

effectively at scale? That remains to be

seen. Manufacturing solidstate batteries

requires different processes, different

equipment, and different quality

measures than conventional lithium ion

production. The industry has decades of

experience optimizing lithium ion. Solid

State is starting from scratch. Each

company we've discussed is forging its

own path to viable solid state

batteries. Some are betting on sulfides

others on oxides or polymers. Some are

going for pure solid state and others

are accepting small amounts of liquid

electrolyte as a pragmatic compromise.

This diversity of approaches is both

encouraging and concerning. It's

encouraging because it means lots of

smart people are attacking the problem

from different angles. It's concerning

because it suggests that there isn't a

clear winner yet and some of these bets

just won't pay off.

So, where does this leave solidstate

batteries? It's challenging to separate

the hype from facts. And how many of

these solid state batteries will really

truly be all solid state when you crack

them open? As promising as these

techniques and pilot plants can be

there's still nothing solid to hang on

to just yet. The sheer variety of

technologies under the umbrella of the

term solid state battery means that it's

really difficult to give the technology

a singular rating on NASA's

technological readiness or TRL scale.

Some of these like the new developments

from Huawei and DICP are still on the

lab bench putting them at a five at

best. The various auto manufacturers are

plowing ahead with tech that's passed a

real world demo or two. Others are so

confident in their tech that they're at

the pilot plant stage. Fleet proven

systems like this would mean a TRL of

seven or eight. I think by now it's

clear that the deadlines like 2028 or

2030 are more aspirations than promises.

It's very possible that all these

deadlines are just going to be pushed

forward yet again as the

commercialization process hits more road

bumps. After all, a pilot plant is only

a test and sometimes you fail a test.

It's all part of the process and

completely normal. And yet, the

challenges of mass-producing a true

solid state battery and a history of

people saying, "The next year or two, we

promise," leaves me a little more

skeptical. I really hope I'm wrong in

the next few years do see a dawning of

the solid state battery age. But I'm not

holding my breath. Again, these

commercialization road bumps are part of

the process. On the other hand, who

cares if a battery is not in fact fully

solid state, so long as it does what it

says on the tin. If a battery really can

charge to 80% in less than 12 minutes

while maintaining a decent cycle life

and energy density, then I'm not going

to get hung up on whether it's a true

all solidstate battery or a semi-olidate

battery. The MG4 proves that solidstate

adjacent technology can reach consumers

at reasonable prices. The Mercedes test

proves that range improvements are real

and substantial. The pilot plants prove

that major manufacturers are committed

enough to invest serious money. All

that's to say, you better believe it

that we'll be revisiting these companies

in 2028 and 2030 to see if any of these

promises materialize. For now, I'd say

we're in the cautiously optimistic but

maintaining healthy skepticism zone. Not

the revolution we were promised a decade

ago, but meaningful progress towards

better, safer batteries is happening.

But what do you think? Are solid state

batteries going to actually happen and

become another great option for energy

storage? Jump in the comments and let me

know. You can also check out the

extended cut of this video over on

Patreon if you'd like to join. The

link's in the description. Be sure to

listen to my follow-up podcast still to

be determined while we keep this

conversation going. Keep your mind open

stay curious, and I'll see you in the

next