When comparing battery types based on energy density, the following is a descending order of energy density for common battery chemistries:

1. Lithium-Ion (Li-ion) Batteries:
   • Energy Density: Approximately 150-250 Wh/kg (Watt-hours per kilogram). Li-ion batteries are known for their high energy density, making them popular in portable electronics and electric vehicles.
2. Lithium-Polymer (LiPo) Batteries:
   • Energy Density: Approximately 130-220 Wh/kg. LiPo batteries have slightly lower energy density compared to Li-ion batteries but are still high compared to other chemistries. They are used in applications requiring lightweight and flexible batteries.
3. Nickel-Metal Hydride (NiMH) Batteries:
   • Energy Density: Approximately 60-120 Wh/kg. NiMH batteries have a lower energy density compared to lithium-based batteries but offer good performance and are widely used in hybrid vehicles and other applications.
4. Alkaline Batteries:
   • Energy Density: Approximately 80-120 Wh/kg. Alkaline batteries have a comparable energy density to NiMH batteries but generally offer lower performance in high-drain applications.

Summary:

• Highest Energy Density: Lithium-Ion (Li-ion) Batteries
• Second Highest: Lithium-Polymer (LiPo) Batteries
• Third Highest: Nickel-Metal Hydride (NiMH) Batteries
• Lowest Energy Density: Alkaline Batteries

Lithium-based batteries (Li-ion and LiPo) lead in energy density, making them suitable for high-performance and portable applications. NiMH and alkaline batteries offer lower energy densities but are still widely used in various applications due to their other beneficial characteristics.