“Lithium batteries” refer to a general term for batteries that use metallic lithium or lithium alloys as the negative electrode active material and a non-aqueous electrolyte solution. Li is the lightest element with the lowest relative atomic mass and the most negative standard electrode potential among known metallic elements. Therefore, batteries composed of lithium metal as the negative electrode have the characteristics of high specific energy and high battery voltage. They also have advantages such as stable discharge voltage, wide operating temperature range (-40°C to 50°C), good low-temperature performance, and long storage life. Since lithium is a highly reactive chemical element, it oxidizes quickly in the air, leading to battery failure. Therefore, the production, maintenance, and transportation of lithium batteries require very strict environmental control and operating procedures. Lithium batteries have advantages such as high single-cell voltage, lightweight, and high energy density, so they are widely used in mobile electronic devices, electric vehicles, energy storage systems, and other fields.
“Lithium-ion batteries” use carbon materials as the negative electrode and lithium-containing compounds as the positive electrode, without metallic lithium present, only lithium ions. Lithium-ion batteries use the movement of lithium ions between the positive and negative electrodes to achieve charging and discharging. During the charging and discharging process, Li+ ions shuttle back and forth between the two electrodes through intercalation and deintercalation: during charging, Li+ ions deintercalate from the positive electrode, pass through the electrolyte, and intercalate into the negative electrode, putting it in a lithium-rich state; the reverse happens during discharging, often metaphorically termed as a “rocking chair battery.” People commonly refer to everyday items such as smartphone lithium-ion batteries or electric vehicle lithium-ion batteries as simply “lithium batteries,” but this term is not accurate and has become a habit over time. Both lithium batteries and lithium-ion batteries belong to the lithium battery family, with lithium-ion batteries being a subtype; not all lithium batteries are lithium-ion batteries.
So, what are the types of “true” lithium batteries that use metallic lithium as the negative electrode?
- Li-MnO2 batteries: The negative electrode is metallic Li, and the positive electrode is specially heat-treated MnO2 powder. Li-MnO2 batteries share characteristics of lithium batteries such as stable discharge voltage, wide operating temperature range, and low self-discharge, thus exhibiting good stability and safety. They are commonly used in computer motherboards, cameras, and car key remotes.
- Li-SO2 batteries: The negative electrode is metallic Li, and the positive electrode is liquid SO2. Li-SO2 batteries have high power output, excellent low-temperature performance, stable operating voltage, and good safety. They are commonly used in military equipment, smart instruments, marine environmental detection, and life-saving equipment.
- Li-I2 batteries: The negative electrode is metallic Li, and the positive electrode is a complex of I2 and polyethylene glycol pyridine. These batteries have high reliability, and long life, and are thus mostly used in pacemakers.
“Lithium-ion batteries” are commonly used in smartphones (with cathode materials mostly being lithium cobalt oxide) and electric vehicles (with cathode materials like lithium iron phosphate or ternary materials). There are differences in performance, safety, etc., between lithium batteries and lithium-ion batteries. Lithium-ion batteries have higher energy density, longer life, and better environmental friendliness but require stricter safety control and management. Therefore, consumers need to choose between lithium batteries and lithium-ion batteries based on their actual needs and usage environment.