A lithium-ion battery naturally degrades over time and the number of years covered since its first use until the time it has to be replaced is called its lifespan or service life. The average lifespan of a lithium-ion battery is between 300 to 500 cycles. It discharges and recharges normally for the first 300 cycles, which is equivalent to about one year.
Figure 1. Lithium-ion battery’s normal capacity fade rate. Obtained from [Intel]
On average, after 300 full cycles, the battery capacity or battery life – the amount of energy it can store – has already dropped to 80% of its initial capacity. It is important to note that this decline occurs gradually as shown in the image above, indicating a normal phenomenon brought about by the continuous chemical reactions in a lithium-ion battery (see image below).
Figure 2. Chemical reactions occurring inside a lithium-ion battery during discharge. Recharging the battery by applying small voltage reverses this reaction. Obtained from [Woody et al 2020]
The above phenomenon is called “capacity fade.” It is one of the two forms of lithium-ion battery degradation. The second form is called “power fade,” which is defined as the decrease in the amount of power a battery can provide due to an increase in the battery’s internal impedance. [Woody 2020]
A lithium-ion battery’s life span is very dependent on how a consumer uses the device. With abnormal operating conditions, like those summarized in the diagram below, the battery’s capacity will decline faster than expected, eventually resulting in shortened lifespan and the premature replacement of a smartphone. The question now is how do we smartphone users make full use of our rechargeable batteries before we purchase another one?
Figure 3. Abnormal operating conditions that contribute to premature degradation of a lithium-ion battery. Obtained from [Woody 2020]
Below are some guidelines on how a smartphone user can preserve the health of its lithium-ion battery, collected from various reliable sources. Being able to prevent premature degradation of your batteries not only gives you cost savings, but also helps in reducing toxic wastes from defective electric devices, and other environmental impacts from manufacturing smartphone batteries.
Do not expose your smartphone to extreme ambient temperatures
The acceptable operating temperature of your device is between 16°C and 22°C. More importantly, avoid using and charging it to temperatures beyond 35°C as this will cause irreversible damage to the battery’s capacity. That means, smartphones should not be placed near radiators, furnaces, heaters, and other heat-generating devices. The decline in battery life also occurs to devices when it is subjected to extremely cold environment (less than 10 °C), although the effect is temporary.
Get rid of those phone cases when charging
Recharging your smartphones noticeably generates heat, which has an irreversible negative impact on a battery’s lifespan as previously mentioned. Removing those plastic and metal phone cases, which come in various designs, just before recharging will ensure effective heat dissipation during a recharge. In addition, put your phones in a cool area during charging to avoid additional heat accumulation and worse, overheating.
Do not expose to damp environment
Exposing batteries and other electric devices to high humidity might cause moisture absorption, which then leads to internal chemical reactions producing combustible gases, and eventually failure of the battery. Use your smartphones in cool and dry places.
For long-term storage, half-charge and turn it off
If you plan to store your device for months without using it, do not charge it fully, neither completely discharge it. If the battery is at 100% for a long time, its capacity will go down. On the other hand, if the battery is nearly or completely discharged, the phone can go into a “deep discharge state.”
The best way to store a battery is to charge it up to about 50% before turning it off for storage. Keep it in a cool and dry area, around 10°C to 35°C. Do not store it in damp or humid areas. Moisture absorption is critical in electric devices’ health.
Do not wait too long before recharging
Waiting for your smartphone to fully drain its battery before recharging it is not as efficient as it may look because this habit actually makes the battery heat up and thus, eventually decreases its lifespan. Instead, recharge your smartphone right away when it reaches a charge state of about 20 to 40%. Avoid pushing it further down to 10%.
Recharge up to around 80% only
A 2015 study by Muenzel et al has analyzed that selecting the maximum daily charging state can double a battery’s lifespan.
In addition, the case study has specified that the daily charge state of smartphone’s lithium-ion batteries should play between 21% and 81%, that is, an average of 51% state of charge.
A device like Chargie can help you do that automatically. You can basically forget you’re using it. Just plug in your phone and Chargie will limit charging to whatever value you wish. It can also do much more: you can keep your phone to, say, 60% during the night, and only top it up to 90% or whatever value you wish before you wake up. This way your battery will stay healthier for much longer.
Minimize phone usage
Considering that a battery’s lifespan in years depends on how many cycles of discharge and recharge have occurred and that the battery’s capacity declines gradually with these cycles, then it is imperative that you can prolong your smartphone battery’s lifespan if you can manage to lower this number of cycles over a period of time.
That is, control your battery’s energy consumption by following tips on increasing battery life – such as using energy-saving modes, avoid using vibrations, etc. For instance, without managing your daily battery consumption, you can get 300 cycles for a year. However, if you can put your energy consumption to a minimum, at the same operating or usage conditions as the first case, then you can achieve 300 cycles for maybe one-and-a-half years or more.
According to Nokia and Sony, your smartphone battery will incur potential irreversible damages if left charging after it has already reached a charge state of 100%. Nokia further advises that recharging smartphones should never last for more than 12 hours. Again, a Chargie device can help you do that. Its anti-aging mechanism literally stops current from flowing into your battery and doesn’t continually and obsessively top it up.