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EP-4742288-A1 - SEMICONDUCTOR ELECTRICITY STORAGE MATERIAL, ELECTRICITY STORAGE BODY, LAYERED ELECTRICITY STORAGE BODY

EP4742288A1EP 4742288 A1EP4742288 A1EP 4742288A1EP-4742288-A1

Abstract

[Problem] To provide a semiconductor electricity storage material, an electricity storage body and a layered electricity storage body, including a biomaterial and having semiconductor properties and simultaneously electricity storage properties. [Solution] The semiconductor electricity storage material has fibers containing chitin or chitosan as the main component, is in the form of a sheet, and has a density of 2 g/cm 3 or less. The fibers are preferably crystallized and amorphous fibers and preferably include bundles or particulate aggregates of chitin nanofibers or chitosan nanofibers with a width of 3 to 400 nm. The semiconductor electricity storage material is preferably an n-type bulk semiconductor and preferably has N-type negative resistance.

Inventors

  • FUKUHARA, MIKIO
  • YOKOTSUKA, Tomonori
  • HASHIDA, TOSHIYUKI

Assignees

  • Tohoku University

Dates

Publication Date
20260513
Application Date
20240516

Claims (8)

  1. A semiconductor electricity storage material, having fibers containing chitin or chitosan as a main component, being in form of a sheet and having a density of 2 g/cm 3 or less.
  2. The semiconductor electricity storage material according to claim 1, wherein the fibers are crystallized and amorphous fibers.
  3. The semiconductor electricity storage material according to claim 1, wherein the fibers include bundles or particulate aggregates of chitin nanofibers or the chitosan nanofibers with a width of 3 to 400 nm.
  4. The semiconductor electricity storage material according to claim 1, wherein a specific surface area of the fibers is 750 to 900 m 2 /g.
  5. The semiconductor electricity storage material according to claim 1, being an n-type bulk semiconductor.
  6. The semiconductor electricity storage material according to claim 1, having N-type negative resistance.
  7. An electricity storage body, having: the semiconductor electricity storage material according to any one of claims 1 to 6, and a pair of metal electrodes each provided on both surfaces of the semiconductor electricity storage material so that the semiconductor electricity storage material is put between the electrodes.
  8. A layered electricity storage body, comprising a layered body obtained by stacking a plurality of the electricity storage bodies according to claim 7.

Description

Field of the Invention The present invention relates to a semiconductor electricity storage material, an electricity storage body and a layered electricity storage body. Description of Related Art Semiconductors are electronic parts which have been used for light electric elements such as transistors using properties in which the conductivity is remarkably changed due to introduction of impurities and influences of e.g. heat, light, magnetic field, voltage, current and radiation, and are essential parts for electronic equipment. The semiconductors have been widely applied to e.g. particularly various types of diodes, transistors, FETs, SITs, RAMs, ROMs and CCDs. In recent years, high-performance IT products such as cellphones and micro-storage devices and electric vehicle batteries have rapidly evolved and semiconductors which are yet smaller and have high capacity and high functions such as memory have been increasingly demanded. Products adapted to a smart grid (next generation power grid) society fitted for green innovation (low-carbonization) to prevent global warming particularly have been demanded. The expansion of the market for condensers such as inverters for e.g. motor vehicles, IT equipment and energy saving has steadily moved at an average annual rate of about 3.7% and reached 1 trillion market. Inorganic materials and organic materials have been used in the past as a material for such semiconductors. These are all artificial and many materials are harmful to global environmental preservation and survival for organisms including human living. Therefore, as the semiconductor materials used, those not using toxic elements such as arsenic, lead, cadmium, beryllium and mercury and environmental pollutants such as lithium, chromium and sulfur are desired. That is, even for semiconductors, inexpensive materials harmless to health have been demanded. The semiconductors are roughly classified into for high voltage power circuits (heavy electricity) and for electronic and electrical equipment circuits (light electricity) depending on uses. Among these, as main semiconductor materials for electronic and electrical equipment circuits in the light electric field, Si and compound semiconductors are mainly used and a metal/semiconductor-type transistor including an amorphous Ni-Nb-Zr-H alloy as a material, for example, have been developed by the present inventors (see e.g. Non-Patent Literatures 1 to 5 or Patent Literature 1). Organic semiconductors are also heavily used as a material for organic ELs, which have been a main member for television and smartphone products, and for organic solar batteries. Among parts of organic semiconductors, there are those causing an increase in carbon dioxide and also those becoming microplastics causing marine pollution and the production of such parts has been avoided around the world from the viewpoint of animal and plant protection and global environmental preservation. From this viewpoint, the development of semiconductors which have a smaller environmental burden on production and disposal and a lightweight and use wood and plant fibers (cellulose) obtained from plants having high elastic performance is the direction of global environmental preservation which fits the circumstances. Semiconductors using a carbon neutral biomaterial have not been used in the past; however, n-type semiconductors from kenaf, a non-wood annual grass, and conifers which typify wood are discovered by the present inventors by focusing on the use of global environment-friendly and recyclable plant fibers. Direct current/alternating current elements, insulator/metal conductive switching elements, biomaterials having rectification action and ambient temperature transistors made using a fiber material from cellulose molecules obtained from wood and plant fibers (pulp) have been developed (see e.g. Non-Patent Literature 6). Condensers (capacitors), meanwhile, are originally electronic parts which store and release a charge (electrical energy) by capacitance, and play roles as e.g. power supply stability, a backup circuit, a coupling element and a noise filter in mobile electronic equipment such as personal computers and cellphones, and thus are essential parts for electronic equipment. In recent years, high-performance IT products such as cellphones and micro-storage devices and electric vehicle batteries have rapidly evolved and condensers which are yet smaller and have high capacity and high functions such as memory have been increasingly demanded. Conventional condensers include, for example, amorphous titania, amorphous alumina or an amorphous polymer as a material and are characterized by having unevenness of an electric insulator on the surface thereof (see e.g. Non-Patent Literatures 7 to 15). The condensers, however, are all artificial, and it is not preferred to use a condenser using a harmful compound such as Li or Pb in view of global environmental preservation. On the contrary, by focu