01The basics
How a lithium-ion battery works
Every lithium-ion battery is a sandwich: two electrodes, a liquid electrolyte between them, and a thin separator that keeps them apart. Energy is stored by moving lithium ions from one side to the other and back again.
Discharging: powering your device
Lithium ions leave the graphite, cross the electrolyte and separator, and settle into the cathode. Electrons can't take that route, so they travel through the outside circuit instead. That flow of electrons is the current that runs your phone, laptop, or e-bike.
Anode (−)
Usually graphite: stacked sheets of carbon. Lithium tucks in between the sheets when the battery is charged.
Cathode (+)
A lithium metal oxide such as NMC or LFP. It takes lithium back in as the battery powers your device.
Electrolyte
A lithium salt dissolved in liquid solvent. Ions can travel through it but electrons can't, and in most cells it's flammable.
Separator
A porous plastic film thinner than a human hair. Ions pass through it, but it keeps the two electrodes from touching.
Where things go wrong: in a healthy cell, lithium slips neatly between the graphite sheets every time it charges. When it doesn't, it builds up on the anode's surface instead, and that buildup is how dendrites begin.
02The problem
What are dendrites?
Every time a lithium battery charges, lithium ions move to the negative electrode. Ideally they tuck neatly inside it. Under the wrong conditions, the lithium instead grows as thin, branching metal filaments called dendrites.
Short circuits
Accelerated capacity loss
Thermal runaway and fires
How a dendrite actually forms
Play through the five stages, or tap any step to jump to it.
Stage 1 of 5 · not to scale
Watch dendrites grow atom by atom
Our kinetic Monte Carlo simulator lets you change the conditions and see what the lithium does.
03Why it matters
Where this shows up in daily life
Lithium-ion batteries are in nearly everything that holds a charge: phones, laptops, power tools, power banks, e-bikes and scooters, hearing aids, electric vehicles, and grid-scale storage. When they fail, the costs add up fast.
E-bikes & scooters
Consumer electronics
Electric vehicles
Aviation
- Cost of the Samsung Galaxy Note7 recall
- $0B+
- Cost of the Chevy Bolt EV battery recall
- $0B
- Deaths from lithium-ion battery fires in New York City in 2023
- 0
- Burn time of the 2021 Victorian Big Battery fire
- 0 hrs
Source: Samsung via AP — ≈$5.3B total
Source: GM / LG — ~$1.9B reimbursed, ~$2B total
Source: NYC Mayor's Office / FDNY
Source: Technical investigation — burned out in ~6 hrs
04Best practices
Keeping dendrites at bay
A few everyday habits keep lithium plating slow, even, and manageable.
Charge at Moderate Rates
Fast charging pushes ions in faster than they can settle evenly, encouraging dendrite growth.
Try it on your phone: turn on Optimized Battery Charging (iPhone) or Adaptive Charging / Battery Protection (Android) in your battery settings. Your phone learns your routine and eases off the last stretch of charging instead of rushing to 100%.
Avoid Charging in the Cold
Charging below freezing slows ion diffusion, making uneven, dendrite-prone plating more likely.
Don't Overcharge
Sitting at 100% for long periods stresses the electrode and encourages filament growth.
Keep Temperatures Moderate
Excess heat during charging accelerates degradation and uneven lithium deposition.
Try it: how risky is this charge?
Pick the conditions and see how they stack up.
Plating risk
Elevated
- Save fast charging for when you need it. A standard charger is gentler day to day.
- Turn on Optimized / Adaptive Charging so the phone holds at 80% until you need it.
An illustration of which conditions matter, not a lab measurement.
05Your battery
Personal advice for the batteries you own
Tell us what you use and how you charge it, and get advice that fits. Then see how much capacity your own battery has left.
Battery Dendrites
My battery plan
iPhone · 1–2 years old · 11/1/2026
Habit score
70
A few easy wins
Most batteries still hold close to their original charge at this age.
What to change, most important first
- 1.
You said: charge to 100% and keep it there
iPhone 15 or later: Settings › Battery › Charging, then set the limit to 80%. iPhone 14 or earlier: Settings › Battery › Battery Health & Charging, then turn on Optimized Battery Charging.
Sitting at a full charge for hours puts extra stress on the battery, and a nearly full anode is where lithium is most likely to plate. (Linked to lithium plating.)
- 2.
You said: use fast charging most of the time
Keep fast charging for when you're in a hurry, and use a standard charger overnight or at your desk.
Fast charging pushes lithium into the anode quickly. If it arrives faster than the anode can take it in, some of it plates on the surface instead. (Linked to lithium plating.)
See your iPhone's battery health
- Open Settings and tap Battery
- Tap Battery Health (called Battery Health & Charging on some older models)
- Check Maximum Capacity. On iPhone 15 and later, the cycle count is on the same screen
Maximum Capacity compares your battery with when it was new. Apple designs iPhone 15 and later to keep about 80% after 1,000 full cycles, and earlier models after 500.
Source: https://support.apple.com/108055
My reading: ____________ % capacity on ____ / ____ / ______
A rough guide to charging habits, not a measurement of your battery. Made with the battery check-up on Battery Dendrites, a student project in collaboration with Prof. Ming Tang’s group at Rice University.
Your battery check-up
Advice for your device and your habits
Nothing you enter leaves your browser.
Habit score
A few easy wins
Most batteries still hold close to their original charge at this age.
Your top changes · iPhone
- 1
iPhone 15 or later: Settings › Battery › Charging, then set the limit to 80%. iPhone 14 or earlier: Settings › Battery › Battery Health & Charging, then turn on Optimized Battery Charging.
Sitting at a full charge for hours puts extra stress on the battery, and a nearly full anode is where lithium is most likely to plate.
Linked to lithium plating - 2
Keep fast charging for when you're in a hurry, and use a standard charger overnight or at your desk.
Fast charging pushes lithium into the anode quickly. If it arrives faster than the anode can take it in, some of it plates on the surface instead.
Linked to lithium plating
A rough guide to your habits, not a measurement of your battery.
Check your capacity
See your iPhone's battery health
Maximum Capacity compares your battery with when it was new. Apple designs iPhone 15 and later to keep about 80% after 1,000 full cycles, and earlier models after 500.
Apple support- 01Open Settings and tap Battery
- 02Tap Battery Health (called Battery Health & Charging on some older models)
- 03Check Maximum Capacity. On iPhone 15 and later, the cycle count is on the same screen
Check your device
What to do for the batteries you own
Your phone charges every day, so small habits add up.
Phones are charged more often than almost anything else you own. Heat and long stretches at 100% are what wear the battery fastest.
The one habit
Let the software help
Built-in charge limits keep the battery out of the highest charge levels, where lithium is most likely to plate.
Do
- Turn on Optimized or Adaptive Charging so the phone waits near 80% until you need it
- Use the charger that came with it, or one from a reputable brand
- Take off a thick case if the phone gets hot while charging
Avoid
- Charge it under a pillow, on a bed, or in a hot car
- Keep using it if the screen or back starts lifting away from the frame
06Chemistry
The anode decides how easily dendrites grow
Dendrites grow on the anode, the negative electrode that lithium flows into while charging. What it's made of changes how likely lithium is to pile up as metal, and it trades off against how much energy the battery holds and how long it lasts.
| Property | Lithium metal | Graphite | Silicon | Lithium titanate (LTO) |
|---|---|---|---|---|
| Dendrite growth risk | Very high | Intermediate | Moderate | Very low |
| Typical energy density | ~350–500 Wh/kg Prototype cells; highest possible | ~200–300 Wh/kg Today's standard | ~300–400+ Wh/kg About 10× graphite's capacity | ~60–100 Wh/kg Lowest of the four |
| Thermal stability | Low Very reactive, melts at ~180 °C | Moderate Its protective surface film breaks down when overheated | Moderate Similar to graphite | Very high Highly resistant to thermal runaway |
| Typical cycle life | ~100–500 Still in development | ~1,000–3,000 Depends on the cathode | ~500–1,000 More silicon means fewer cycles | ~5,000–20,000+ Barely changes size as it charges |
| Why the dendrite risk | Nothing holds the lithium, so it plates bare metal onto bare metal every charge. | Stores lithium very close to the voltage where lithium metal plates out. | Swells up to ~3× as it charges; the cracking makes deposition uneven. | Works at a voltage far above where lithium metal can form. |
| Where you'll find it | Next-generation and solid-state research cells | Most phones, laptops, and EVs today | Blended into graphite in some newer phones and EVs | Electric buses, grid storage, very fast-charging systems |
Energy density is for a full cell, and all values are typical ranges. Real numbers depend on the cathode, cell design, and how the battery is used.
07Detection
How researchers actually see dendrites
Dendrites are microscopic and hidden inside a sealed cell, so seeing them takes X-rays, electron beams, and specially built cells.
X-ray Tomography (CT)
Like a hospital CT scan for batteries. Powerful X-rays build a 3D picture of a sealed cell, showing where dendrites grow and when they reach the separator, all without opening it.
Scanning Electron Microscopy (SEM)
A focused electron beam images the anode surface in fine detail, showing whether the lithium formed a smooth layer, a mossy mat, or sharp needles.
Cryo-Electron Microscopy
Lithium is so delicate that an electron beam can damage it. Freezing the sample first protects it, so researchers can image dendrites down to individual rows of atoms.
In-Situ Optical Microscopy
Cells built with a see-through window let researchers watch dendrites sprout and branch live, while the battery is charging.
Nine techniques, 28 peer-reviewed papers
The References page covers these four plus TEM, neutron imaging, AFM, impedance spectroscopy, and ultrasound, with links to the original studies.
08Engineering
What's being done about it
None of these fully solve dendrite growth on their own. Most products combine several.
Solid Electrolytes
A rigid electrolyte can physically resist penetration in a way liquid electrolytes can't.
Artificial SEI Coatings
Engineered protective layers promote a smoother, more uniform flow of lithium ions.
Pulse Charging
Alternating charge and rest pulses give ions time to settle evenly instead of piling up.
Smart Battery Management
ML-driven battery management systems adjust current in real time based on temperature and impedance.
09Reference
Glossary
The vocabulary you'll run into throughout this site.
9 terms found
- Anode
- The electrode that hosts lithium during charge (graphite or metal); where dendrites typically nucleate.
- Cathode
- The positive electrode that lithium ions travel toward during discharge, and away from during charging.
- Electrolyte
- The liquid, gel, or solid medium that carries lithium ions between the anode and cathode.
- Separator
- A thin, porous membrane that physically keeps the electrodes apart while still letting ions pass through.
- SEI Layer
- Solid Electrolyte Interphase — a thin passivation film that forms on the anode from electrolyte breakdown, shaping how evenly lithium plates.
- Thermal Runaway
- A self-accelerating chain reaction where heat from an internal failure triggers more heat, often ending in fire or explosion.
- Dendrite
- A branching, needle-like filament of metallic lithium that forms from uneven plating during charging.
- Cycle Life
- The number of charge/discharge cycles a battery can undergo before its usable capacity drops significantly.
- Energy Density
- How much energy a battery stores per unit of weight or volume — the main driver of range and runtime.