The energy density of lithium-ion batteries falls under the range 125-600+ Wh/L whereas, for lead acid batteries, it is 50-90 Wh/L. This drastic variation is due to the fact that lead acid batteries are much heavier than lithium-ion batteries, which in turn results in less energy density. Lead acid batteries also need more space to fit in.
Lithium-ion batteries are lighter and more compact than lead-acid batteries for the same energy storage capacity. For example, a lead-acid battery might weigh 20-30 kilograms (kg) per kWh, while a lithium-ion battery could weigh only 5-10 kg per kWh.
Lead Acid Batteries Lead-acid batteries consist of lead dioxide (PbO2) and sponge lead (Pb) plates submerged in a sulfuric acid electrolyte. The electrochemical reactions between these materials generate electrical energy.
Disadvantages: Heavy and bulky: Lead acid batteries are heavy and take up significant space, which can be a limitation in specific applications. Limited energy density: They have a lower energy density than lithium-ion batteries, resulting in a lower capacity and shorter runtime.
Most lithium-ion batteries are 95 percent efficient or more, meaning that 95 percent or more of the energy stored in a lithium-ion battery is actually able to be used. Conversely, lead acid batteries see efficiencies closer to 80 to 85 percent.
Both lead-acid batteries and lithium-ion batteries are rechargeable batteries. As per the timeline, lithium ion battery is the successor of lead-acid battery. So it is obvious that lithium-ion batteries are designed to tackle the limitations of lead-acid batteries.