With anticipated upgrade in battery technology this 2015, studies have shown that  Li-ion battery will have less than five percent greater unit charge compared to a 2014 model of the same dimensions and voltage. With this, longer battery life is likely to remain a key factor for those choosing their next smartphone.

However, most new smartphone owners may still get a 15 percent increase in battery life, but this will mostly be due to other factors. New devices will benefit from efficiency improvements in the components that draw power from batteries as well as from better software.  Further, there will be an expectation of the mAh of the average battery shipped in smartphones increasing by up to 25 percent this year.

Due to the increase in average size of smartphones sold, with battery capacity rising at a greater pace than screen area: However, battery life might not go up to 25 percent fully because larger screens use more power and newer phones typically offer increased functionality, leading to more intensive usage. Processor and connectivity speeds will see the biggest increment which is not exactly what the consumer is looking to get in the new devices but the battery breakthrough which is thanks to the introduction of Li-ion technology which according to Moore's Law, there will be consistent, significant increase in performance at the same point.

Indeed, there is unlikely to be anything more than a modest improvement from Li-Ion in 2015 or at any time in the future. At most it may yield just a further 30 percent performance before hitting a ceiling, with perhaps a 20 percent improvement by 2017. Any major inflection in battery performance would require the use of different technology which is not about to change in 2015 or even before the end of this decade.

The lack of progress in smartphone battery capacity is not for lack of trying but simply because it is extremely difficult to identify a battery chemistry that is better and suitable for use in the highly diverse operating environments in which the billions of consumer electronic devices we own are used.

Instead, device component advances will reduce power consumption which could be the only way consumers get more hours of usage between charges. This is definitely the typical smartphones specs; the screen, the processor and the radio. They are likely to yield the biggest improvements in getting the most minutes out of each milliwat. The processor used in many 2015 smartphones should be significantly more efficient than 2014 models, delivering a 30-40 percent increase in processing power per watt.