The Truth Behind Lithium Ion Batteries

Smartphones are an indispensable extension of ourselves and a staple part of our daily lives, connecting us with people and the world, extracting information, accessing digital tools, serving as personal assistants, and keeping us entertained. To quote Elon Musk, our symbiotic relationship with these pocket-sized machines, makes us a loose interpretation of a “cyborg”. Yet, behind the sleek screens and impressive capabilities of these devices lies a critical component that makes it all possible – the lithium-ion battery.

The Source of All Power?

A battery is essentially a device that stores energy in the form of chemical reactions and releases it as electricity. If the processor chipset is the brain of any smart device, the battery would be the heart that supplies blood and life to it.

“When you talk about portable devices, whether a notebook, iPod, or phone, it’s all about power; it’s all about batteries.” – Steve Jobs.

The most common type of batteries used in smartphones, laptops, EVs, and other electronic devices are the lithium-ion batteries (LiBs). The lithuim-ion battery was introduced to handheld mobile devices in early 90s, replacing their predecessor, the Nickel-Cadmium battery to quickly become prized for their high energy density out put which offers a high energy-to-weight ratio, allowing them to store a significant amount of energy in a compact form. This is crucial for keeping smartphones slim and lightweight.

LiBs also have a trait of rechargeability, allowing users to repeatedly charge and discharge their smartphones without the memory effect (a reduction in battery capacity) seen in older battery technologies. Well-maintained lithium-ion batteries can also last for several years, making them suitable for the relatively long lifespan of smartphones, in addition to providing a stable and relatively high voltage throughout their discharge cycle, ensuring consistent performance.

How does a Lithium-ion battery work?

Lithium-ion batteries consist of three essential components: a cathode, an anode, and an electrolyte. The cathode typically employs lithium cobalt oxide, while the anode is predominantly composed of graphite. The role of the electrolyte, which can be in the form of a liquid or gel, is to facilitate electrical conduction between the cathode and anode.

During the charging process, electrical energy is supplied to the battery, prompting the migration of lithium ions from the anode to the cathode. This transfer results in the development of a positive charge on the cathode and a corresponding negative charge on the anode. Upon reaching full charge capacity, the lithium ions accumulate on the cathode, poised to be converted into electricity when the battery is engaged.

When a smartphone is powered on and actively used, the stored electrical energy stored in the lithium ions residing on the cathode is directed through the circuitry to provide the necessary power for the device’s operation. Concurrently, as the lithium ions return to the anode, the battery undergoes discharge, leading to a gradual reduction in the phone’s available power.

Apple’s iOS allows users to check-in on their battery health overtime in the battery settings, among other options to optimise battery usage. This feature is also present in recent Android 13 updates.

The harsh reality of Lithium ion batteries

Throughout the history of smartphones, the issue of battery deterioration has constantly cast a shadow over the durability of our devices. The belief that battery capacity diminishes over time has frequently been attributed to manufacturing and quality concerns. In truth, this scenario holds true for lithium-ion batteries across all brands and devices. Ultimately, the lifespan of these batteries will draw to a close, and their effectiveness will gradually diminish.

A battery charge cycle encompasses the complete process of discharging and recharging a battery, meaning that depleting a battery to 0% and subsequently recharging it to 100% accounts for one full battery charge cycle. Alternatively, a charge cycle can also be realised by depleting 50% of the battery’s capacity, followed by a recharg e to 100%, with this process being repeated.

The degradation of a battery’s performance is directly linked to the number of charge cycles it has undergone. This phenomenon can be attributed to the intricate chemical composition of Lithium-ion batteries (LiBs) responsible for their degradation.

One notable instance of degradation occurs due to the loss of mobile Li-ions within the battery. These Li-ions are frequently lost through side reactions within the electrolyte, resulting in the formation of compounds that effectively “trap” free lithium. Consequently, this diminishes the number of mobile Li-ions capable of shuttling between the battery’s electrodes, reducing the battery’s overall maximum capacity.

Moreover, battery lifetime can be compromised when the structural integrity of the electrodes is compromised by structural disordering. This structural disarray can emerge during cycling, owing to the movement of Li-ions in and out of the electrodes, thus contributing to battery degradation.

This phenomenon can limit the electrode’s capacity to accept Li-ions into its structure, resulting in a reduction in the capacity of battery. Typically, an average user can anticipate a battery’s lifespan of approximately 2 to 3 years, or roughly 300 to 500 charge cycles, with continuous use, before the onset of noticeable battery degradation.

How to preserve Lithium-ion batteries?

In most cases, even if your device is meticulously maintained, the reality is that batteries will inevitably degrade over time. While the fundamental truth about Lithium-ion batteries remains unchanged, we’ve witnessed certain brands consistently delivering batteries with extended lifespans and superior performance compared to others. The variations can be attributed to a multitude of factors, both on the manufacturer’s side and the consumer’s side.

Furthermore, on a software level, brands take a customised approach to optimise device efficiency and minimise battery consumption, balancing performance and power usage. Apple for example, has new battery health settings that give users that choice to limit charging up to 80%.

Conversely, users also play a pivotal role in prolonging their batteries’ lifespan. It is advisable for users to refrain from overcharging their smartphones or leaving them connected overnight. Charging to the full 100% capacity should be reserved for when it’s necessary (best to maintain at 80%), and it’s recommended not to let the battery deplete to less than 20%, as suggested by Carl Howe, former mobile analyst and Principal of Think Big Analytics.

Most smartphones are automatically programmed to halt charging processes once 100% is reached, to prevent overcharging.

It’s always a wise choice to replace the battery once noticeable degradation significantly impacts efficiency. When opting for battery replacement by ceritifed repair providers, choose original batteries rather than OEM or AA-grade alternatives, as non-original components may lead to certain risks of long-term issues despite their lower cost.

It’s always a wise choice to replace the battery once noticeable degradation significantly impacts efficiency. When opting for battery replacement by ceritifed repair providers, choose original batteries rather than OEM or AA-grade alternatives, as non-original components may lead to certain risks of long-term issues despite their lower cost.