Niobium capacitor
The development of solid electrolyte tantalum capacitors began in the early 1950s as a miniaturized, more reliable low-voltage support capacitor to complement the newly invented transistor. The solution found by R. L. Taylor and H. E. Haring of the Bell Labs was based on experience with ceramics. They ground down tantalum to a powder, pressed this powder into a cylindrical form and then sintered the powder particles into a pellet (“slug”) at high temperatures, between 1500 and 2000 °C, under vacuum conditions. These first sintered tantalum capacitors used a non-solid electrolyte not consistent with the concept of solid state electronics. 1952 a targeted search in the Bell Labs for a solid electrolyte by D. A. McLean and F. S. Power led to the invention of manganese dioxide as a solid electrolyte for a sintered tantalum capacitor.
Film capacitor
Polyimide (PI), a thermoplastic polymer of imide monomers, is proposed for film capacitors called Polyimide-, PI- or Kapton capacitors. Kapton is the trade name of polyimide from DuPont. This material is of interest because its high temperature resistance up to 400 °C. But as of 2012, no specific PI capacitor series film capacitors have been announced. The offered film capacitor, Kapton CapacitorCL11, announced from “dhgate” is a “Type: Polypropylene Film Capacitor”. Another very strange Kapton capacitor can be found at YEC, a Chinese producer of capacitors. Here the announced “Kapton capacitors” are in reality supercapacitors, a completely different technology Perhaps the Kapton film in these supercapacitors is used as a separator between the electrodes of this double-layer capacitor. Kapton films are often offered as an adhesive film for the outer insulation of capacitor packages.