Titanium foil with a thickness of 0.01mm falls within the category of ultra-thin titanium foil. 0.01mm, or 10 micrometers, is approximately only 1/6 to 1/8 the diameter of a human hair. This makes it very soft and has excellent flexibility. Despite its thinness, it still retains the high strength of titanium metal and is stronger than many metal foils of the same thickness. It inherits the inherent properties of titanium metal, being resistant to acids, alkalis, seawater and atmospheric corrosion. Pure titanium is recognized as a metal with excellent biocompatibility and is suitable for use in the medical field. The production, slitting and handling (picking up) of this ultra-thin foil material have extremely high process requirements and are prone to wrinkles, scratches and tears.
This ultra-thin titanium foil, for instance, with a Ti foil thickness 0.01mm, is applied in some high-tech and high-precision fields such as new energy batteries - current collectors, which is currently the largest and most important application area. In lithium-ion batteries, especially in the new generation of solid-state batteries or high-performance lithium batteries, titanium foil is used as the current collector for the negative electrode (or positive electrode), replacing the traditional copper foil or aluminum foil. It has better stability, corrosion resistance and compatibility with new electrode materials.
The core advantage of titanium foil thickness 0.01mm as a current collector lies in some high-voltage and high-energy-density battery systems (such as those using high-voltage cathode materials or certain new electrolytes), where traditional current collectors may be corroded. Copper foil is highly prone to oxidation on the high-voltage positive electrode side, while aluminum foil forms an alloy with lithium on the low-voltage negative electrode side. Titanium forms a dense and stable titanium oxide (TiO₂) passivation film on its surface, which endows it with excellent corrosion resistance throughout a wide electrochemical window, from low potential to high potential. This means that titanium foil can serve as a "bipolar current collector", that is, one side of the same foil is coated with positive electrode material and the other side with negative electrode material, simplifying the cell structure and enhancing energy density. The chemical inertness of titanium enables it to be better compatible with these new electrolytes, ensuring the long-term cycle life and safety of the battery.
During the charging and discharging process of a battery, the active material undergoes volume expansion and contraction, exerting repeated stress on the current collector, which may lead to fatigue fracture of the current collector or separation from the active material. The strength of titanium is much higher than that of aluminium and copper. Although thick 0.01mm Ti foil Gr.1 or Gr. 2 is very thin, its mechanical strength is sufficient to withstand these stresses, reducing the risk of fracture and extending the cycle life of the battery. Meanwhile, the adhesion between its surface and active substances can be well achieved through surface treatment. At present, 0.01mm titanium foil current collectors are not used in all batteries but are mainly targeted at the following high-end fields: next-generation lithium-ion batteries, especially those using high-voltage cathode materials (such as lithium-rich manganese-based). Solid-state batteries are ideal current collector materials compatible with solid-state electrolytes. Supercapacitors are used in situations where extremely high power density and cycle life are required.
Using 0.0004’’ thick titanium foil as the current collector for new energy batteries is a high-performance technical solution oriented towards the future. It has gained significant advantages in terms of corrosion resistance, structural strength, safety and compatibility with new chemical systems by sacrificing some costs and conductivity. With the advancement of titanium processing technology and the reduction of costs, as well as the development of battery systems towards high energy density and high safety, the application prospects of ultra-thin titanium foil in the field of current collectors are very broad.
