Li-ion Cells (Lithium-ion cells) are a type of rechargeable cell that primarily relies on the movement of lithium ions between the positive and negative electrodes for operation. In the discharge cycle, the lithium atoms in the anode are ionized and separated from their electrons. The lithium ions move from the anode and pass through the electrolyte until they reach the cathode, where they recombine with the electrons and are electrically neutralized. According to the positive electrode materials of cells, they can be divided into LiCoO2, LiMn2O4, NCM, NCA, LTO and LiFePO4.The lithium-ion cell here specifically refers to LiCoO2 cell.

Electrochemistry:

Li-ion batteries are also composed of three parts: positive electrode, negative electrode, and electrolyte.

Positive: Li-ions are embedded during discharge and detached during charging.

• Charging: LiCoO2 → Li1-x CoO2 + xLi+ + xe−

• Discharge: Li1-x CoO2 + xLi+ + xe− → Li CoO2

Negative: Li-ion detachment during discharge and insertion during charging.

• Charging: xLi+ + xe− + 6C → LixC6

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Characteristics:

• Rated voltage: 3.6/3.7/3.8/3.85 V

• Standard discharge continuous current: 0.2C

• Maximum continuous discharge current: 0.5C

• Working temperature: Charging: 0-45 ℃ Discharge: -20~60 ℃

• Finished product internal resistance: ≤ 180m Ω

• Specific energy: 100-265 Wh/kg

• Energy density: 250-693 Wh/L

• Specific power: C250 – 340 W/kg

• Charging and discharging efficiency: 80-90%[

• Self-discharge rate: 0.35% -2.5% per month based on charging state

• Cycle durability: 400-1200 cycles

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Advantages:

• High energy density

• High open circuit voltage

• High output power

• No memory effect

• Low self-discharge

• Wide working temperature range

• Fast charging and discharging speed.

Applications: Li-ion batteries are widely used in consumer electronics, industrial instruments, medical equipment, electric vehicles, and other fields. For example, personal digital assistants, personal mobile devices, smartphones and laptops, digital cameras, watches, portable power packs, electric toys, medical devices, solar storage, uninterrupted power supply (UPS) or emergency power backup, monitoring and alarm systems, electric cars and mobile scooters, golf carts and trolleys, etc.