Yes, iPhones use lithium-ion batteries

Every iPhone sold since the original model in 2007 has used a lithium-ion battery. This is the rechargeable battery type that powers the phone — it sits inside the device and stores the electrical energy that runs your screen, processor, and all the apps you use throughout the day.

Lithium-ion batteries are the standard in smartphones, laptops, and tablets because they hold a lot of charge in a small space and can be recharged hundreds of times. Apple has refined the chemistry and design of its lithium-ion batteries over the years, but the basic technology remains the same across all current iPhone models.

Key Takeaways

  • All iPhones contain a lithium-ion rechargeable battery, not a disposable alkaline battery.
  • Lithium-ion batteries degrade over time with repeated charging cycles, which is why older iPhones hold less charge than new ones.
  • Apple's battery health feature in Settings shows you how much capacity your battery has lost and whether it needs replacement.
  • You can replace an iPhone battery through Apple, an authorized repair shop, or a third-party repair service, though costs and warranty coverage vary.

How lithium-ion batteries work in iPhones

A lithium-ion battery moves charged particles (lithium ions) back and forth between two terminals inside the battery cell. When you plug in your iPhone, electrical current pushes ions in one direction, storing energy. When you use the phone, the ions flow the other way, releasing that energy to power the device. This cycle repeats every time you charge and discharge.

The advantage of lithium-ion chemistry is that it can handle hundreds of charge cycles before the battery noticeably degrades. A single charge cycle means draining the battery from 100 percent to zero and back to 100 percent — though Apple counts partial charges too. For example, charging from 0 to 50 percent and then 50 to 100 percent counts as one full cycle.

Why your iPhone battery loses capacity over time

Lithium-ion batteries naturally degrade with use. Each charge cycle causes tiny chemical changes inside the battery that reduce how much energy it can hold. After 500 charge cycles, a typical lithium-ion battery retains about 80 percent of its original capacity. After 1,000 cycles, it may hold only 60 to 70 percent.

Heat speeds up this degradation. If you regularly charge your iPhone in a hot environment or use it while it is charging, the battery ages faster. Cold temperatures also reduce performance temporarily, though they do not permanently damage the battery the way heat does. This is why iPhones sometimes shut down in winter — the battery cannot deliver power as quickly in cold, even if it still has charge stored.

Checking your iPhone battery health

You can see how much capacity your battery has lost by opening Settings, tapping Battery, and selecting Battery Health & Charging. The number shown is the maximum capacity — if it says 85 percent, your battery can now hold 85 percent of the charge it held when new.

Apple recommends replacing your battery when capacity drops below 80 percent if you want peak performance. However, the phone will still work at lower capacities; it just will not last as long between charges. If capacity falls very low (typically below 20 percent), iOS may limit performance to prevent unexpected shutdowns.

Battery replacement options and costs

You have three main routes to replace an iPhone battery. An Apple Store or Apple Authorized Service Provider will replace the battery with an official Apple part and usually charges between $50 and $100 depending on your iPhone model. This option includes a warranty on the replacement battery.

A third-party repair shop (not authorized by Apple) typically charges $30 to $60 and may complete the work faster. However, these shops use non-Apple batteries, and you lose any remaining manufacturer warranty on your phone. Some third-party shops are reputable and use quality parts; others cut corners.

You can also mail your iPhone to Apple or visit a store for an out-of-warranty replacement, which costs more but guarantees an official battery and full warranty coverage. If your iPhone is still under the one-year limited warranty and the battery has degraded due to a manufacturing defect (not normal use), Apple will replace it at no cost.

What to know before replacing your battery

Replacing an iPhone battery yourself is not practical for most people. The battery is glued to the phone's internal structure, and opening the device requires special tools and skill. Attempting a DIY replacement risks damaging the screen, logic board, or other components, which costs far more than a professional replacement.

Before you replace the battery, confirm it is actually the problem. Use the Battery Health feature to check capacity, and review your battery usage in Settings to see which apps drain power fastest. Sometimes a misbehaving app, not a worn battery, is why your phone dies quickly. Restarting the phone or updating iOS can also improve battery performance.

Extending the life of your lithium-ion battery

You cannot stop your battery from aging, but you can slow it down. Keep your iPhone cool — avoid leaving it in direct sunlight or in a hot car. Charge it in a room-temperature environment when possible. Avoid letting the battery drain completely to zero regularly; instead, charge it when it reaches 20 to 30 percent.

Use Optimized Battery Charging, a feature in Settings under Battery Health & Charging. When turned on, your iPhone learns your charging habits and slows charging to 80 percent overnight, then finishes the last 20 percent before you wake up. This reduces the time the battery spends at 100 percent, which is when degradation happens fastest.

Frequently Asked Questions

Can I use a non-Apple charger without damaging the battery?

Yes. Any charger that meets USB-C or Lightning standards will charge your iPhone safely. Slower chargers take longer but do not harm the battery. Very cheap chargers with poor voltage regulation are riskier, but mainstream third-party brands are fine. The charger does not determine battery lifespan — charge cycles and temperature do.

Does leaving my iPhone plugged in overnight ruin the battery?

No, not anymore. Modern iPhones with Optimized Battery Charging stop charging at 80 percent and wait until morning to finish, so the battery does not sit at 100 percent all night. If you turn off this feature, leaving it plugged in does cause faster degradation, but one night will not noticeably damage it.

Why does my iPhone battery drain faster in winter?

Cold slows the chemical reactions inside the lithium-ion battery, so it cannot deliver power as quickly. The battery is not damaged — it will work normally again when it warms up. If your phone shuts down in cold weather, bring it inside and let it reach room temperature before using it.

Is it bad to charge my iPhone to 100 percent every day?

Charging to 100 percent every day does cause slightly faster degradation than stopping at 80 percent, but the difference is small over a year or two. If you use your phone heavily and need the full charge, charging to 100 daily is normal and acceptable. The battery will still last several years.