Yes, tablets use lithium-ion or lithium-polymer batteries
Nearly all tablets sold today run on lithium-ion (Li-ion) or lithium-polymer (LiPo) batteries. These are rechargeable batteries that store electrical energy in chemical form. When you plug in your tablet, the charger reverses the chemical reaction, refilling the battery's capacity. This is why you can recharge your tablet hundreds of times instead of replacing it like a disposable battery.
Lithium batteries became the standard for tablets because they hold more energy in a smaller, lighter package than older battery types. A tablet's battery is usually a flat, rectangular cell (or sometimes multiple cells stacked together) tucked behind the screen and under the back cover. The battery's capacity is measured in milliamp-hours, or mAh — a larger number means longer runtime between charges.
Key Takeaways
- Tablets use lithium-ion or lithium-polymer batteries, which are rechargeable and designed to last hundreds of charge cycles.
- Lithium batteries are preferred because they are lighter and hold more charge than older battery types like nickel-cadmium.
- Battery capacity is measured in milliamp-hours (mAh), and a larger capacity means your tablet will run longer between charges.
- Lithium batteries degrade over time and hold less charge after two to three years of regular use, which is normal wear.
- Tablets are designed so the battery cannot be easily removed or replaced by the user — you must contact the manufacturer or a repair shop.
How lithium batteries work in tablets
A lithium battery has three main parts: two terminals (called the anode and cathode) and a chemical paste between them (the electrolyte). When you use your tablet, lithium ions flow from one terminal to the other through the electrolyte, creating electrical current that powers the screen, processor, and other components. When the battery is empty, plugging in the charger reverses this flow and restores the ions to their starting position.
This cycle can repeat hundreds of times. Most tablet batteries are rated for 300 to 500 full charge cycles before they noticeably degrade — meaning they hold less charge after each cycle. A "full charge cycle" is one complete drain and recharge, not the same as plugging in your tablet every night. If you charge your tablet from 50% to 100%, that counts as half a cycle.
Why tablets don't use other battery types
Older devices used nickel-cadmium and nickel-metal hydride batteries, which were heavier, held less energy, and suffered from "memory effect" — they would lose capacity if you didn't fully drain them before recharging. Lithium batteries have none of these problems and can be recharged at any state of charge without damage.
Alkaline batteries (the kind you buy in packs at a store) are disposable and cannot be recharged. They would be impractical for a tablet because you would need to replace them constantly, and they cannot deliver the high power that a tablet's processor demands. Lithium batteries can supply steady, high power for hours, which is why they became standard in phones, tablets, and laptops.
Battery capacity and how long your tablet runs
A tablet's battery capacity is printed on the device or in the settings menu and is measured in milliamp-hours (mAh) or watt-hours (Wh). A larger number means the battery stores more energy. For example, an iPad Air has a battery around 7,600 mAh, while a Samsung Galaxy Tab S9 has around 8,000 mAh. The difference in capacity is one reason why two tablets of similar size may have different runtimes.
Runtime also depends on what you are doing. Watching video drains the battery faster than reading text because the screen is at full brightness and the processor is working harder. Connecting to Wi-Fi or Bluetooth uses less power than cellular data. If you want your tablet to last longer between charges, lower the screen brightness, close unused apps, and turn off location services when you are not using them.
How battery age affects your tablet
Lithium batteries degrade naturally over time. After two to three years of regular use, you may notice your tablet does not hold a charge as long as it did when new. This is normal wear, not a defect. The battery is still safe to use, but its capacity has decreased because the chemical reactions inside become less efficient with each charge cycle.
Heat speeds up this degradation. If you regularly use your tablet in hot environments or leave it in direct sunlight, the battery will age faster. Keeping your tablet cool and avoiding extreme temperatures can extend battery life. Most manufacturers design tablets so the battery cannot be easily removed by the user. If your battery no longer holds enough charge, you will need to contact the tablet maker or visit an authorized repair shop to have it replaced.
Safety features in tablet batteries
Lithium batteries can overheat or catch fire if they are damaged, overcharged, or exposed to extreme heat. To prevent this, tablets include a battery management system — a small circuit that monitors the battery's temperature and voltage. If the battery gets too hot or the voltage gets too high, the management system cuts off the charger automatically.
This is why your tablet may stop charging when it reaches 100%, even if the charger is still plugged in. The management system is protecting the battery from overcharging, which would shorten its lifespan. It is also why you should use the charger that came with your tablet or a certified replacement. Third-party chargers may not have the same safety controls and could damage the battery or create a fire hazard.
Signs your tablet battery needs replacement
If your tablet shuts down suddenly even though the battery indicator shows 20% or more charge remaining, the battery is likely failing. Another sign is if the tablet becomes very hot during normal use or charging. Swelling or bulging of the back cover can also indicate a failing battery — stop using the tablet when ready and contact a repair shop, because a swollen battery can rupture.
If your tablet is more than three years old and no longer holds a charge for more than an hour of use, battery replacement is a reasonable option. The cost varies by tablet model but is usually between $50 and $150 at an authorized service center. Some repair shops offer battery replacement for less, though you should confirm they use genuine or high-quality replacement batteries.
Frequently Asked Questions
Can I replace my tablet battery myself?
Most tablets are designed so the battery is glued or soldered inside, making user replacement difficult and risky. Opening the tablet yourself can damage the screen, logic board, or battery, and may void your warranty. Contact the tablet manufacturer or an authorized repair shop instead — they have the tools and replacement parts to do it safely.
Is it bad to leave my tablet plugged in overnight?
Modern tablets have battery management systems that stop charging once the battery reaches 100%, so leaving it plugged in overnight will not overcharge it. However, keeping the battery at 100% constantly can slightly speed up aging. If you want to maximize battery lifespan, unplug the tablet once it is fully charged.
Why does my tablet battery drain faster in cold weather?
Lithium batteries work less efficiently in cold temperatures because the chemical reactions inside slow down. The battery is not damaged — it will regain its normal capacity once it warms up. Avoid using your tablet in freezing conditions for extended periods, as extreme cold can permanently reduce battery capacity.
What should I do if my tablet battery is swollen?
Stop using the tablet when ready and do not attempt to open it or remove the battery yourself. A swollen battery can rupture and leak corrosive chemicals or catch fire. Place the tablet in a safe location away from flammable materials and contact the manufacturer or a repair shop for safe disposal and replacement.
Do tablets use the same batteries as phones?
Tablets and phones both use lithium-ion or lithium-polymer batteries, but the physical size and capacity are different. A tablet battery is larger and holds more charge because tablets have bigger screens and larger processors. You cannot swap a phone battery into a tablet or vice versa — each device is designed for its specific battery.