key components of lithium batteries

• The core components of a lithium battery mainly consist of the following four parts:

1. Positive electrode (cathode): Lithium metal oxide materials such as lithium cobalt oxide (LiCoO ₂), lithium iron phosphate (LiFePO ₄), or ternary materials (such as NCM: lithium nickel cobalt manganese oxide) are usually used.
2. Negative electrode (anode): Graphite (carbon material) is commonly used, and lithium ions are embedded between the graphite layers during charging.
3. Electrolyte: an organic solution containing lithium salts (such as LiPF ₆) as a medium for lithium ion migration.
4. Diaphragm: Porous polymer film (such as polyethylene/polypropylene) that allows lithium ions to pass through but prevents direct electron flow, preventing short circuits.

• Key characteristics

1. High energy density: Lithium has a small atomic weight, high oxidation-reduction potential, and can store a large amount of energy per unit mass/volume.
2. No memory effect: can be charged and discharged at any time without affecting capacity.
3. Low self discharge rate: The monthly self discharge rate is about 12%, which is better than nickel hydrogen batteries.
4. Cycle life: Typically 500 to 2000 charge discharge cycles (depending on material and design).

• Security and Challenges

1. Risk of thermal runawa:

Overcharging, high temperature or physical damage may cause electrolyte decomposition, diaphragm rupture, short circuit or even fire (such as lithium cobalt oxide batteries).
2. Improvement direction:

(1) Use more stable positive electrode materials (such as lithium iron phosphate LiFePO ₄).

(2) Optimize electrolytes (such as solid electrolytes).

(3) Add protective circuits (BMS, battery management system).

• Summary:

Lithium batteries achieve the conversion of electrical and chemical energy through the reversible migration of lithium ions between the positive and negative electrodes. Its high energy density and long cycle life make it a core energy technology for portable electronic devices, electric vehicles, and energy storage systems. Future development directions include improving safety (such as solid-state batteries), reducing costs, and increasing energy density.