Lithium Ion batteries have many advantages.

They can be constructed in a wide variety of shapes lithium button cell batteries and sizes, resulting in them being tailored to the available space in the device in which they are to be used.

The batteries are also much lighter than  lithium button cell batteries other equivalents, due to the nature of the material and the high open circuit voltage compared to other batteries. This low weight makes it ideal in hand held and mobile devices for obvious reasons, and popular in these days of high tech gadgets.

Another major advantage is that they do not suffer from memory effect. This is the condition, whereby other rechargeable batteries, if not fully discharged before recharging, lose their maximum energy capacity over time and thus hold less charge.

They also do not have such a drastic self discharge rate as other batteries – just 5% per month, compared with up to 30% per month in other battery types.
However, Lithium Ion batteries are not perfect, and there are drawbacks.

One of these is that their life span depends upon their age – and not the time from which they were charged, or the number of times they have been charged. They begin to lose capacity gradually from the date of manufacture irrespective of the amount of charging cycles they have. Therefore the manufacturing date is useful to know,e specially if there is a big time lapse from manufacture to being used e..g due to storage.

Some Lithium Ion batteries (such as laptop batteries) can lose around 20% of their capacity per year, when stored at normal temperatures. However, when exposed to prolonged higher temperatures, this figure can increase to as much as 35% per year. Another key factor is the charge level – when stored partially charged, these figures can be dramatically reduced.