Electrochemical energy storage devices
摘要
說(shuō)明書(shū)
In exemplary embodiments, gaseous oxygen (O2) and/or oxygen ions (e.g., O+, O?, or O2?) are responsible for charge transport and formation of the electrochemical bonds (redox) by which electrical charge is stored and conserved. Other ionic species may also be useful, depending on the particular construction and chemistry employed, such as nitrogen ions, sulfur ions, chloride ions, protons, etc. A number of transport mechanisms may invoke the passage of ions through the structure of the solid electrolyte layer. For example, vacancies within the structure may be an important source of ion transport.
It will be appreciated that vacancies may represent defects, and may be present when a ceramic has been doped with another chemical which results in a departure from the regularity of the local crystal structure present in the pure ceramic. Such defects may be analogous to “holes” in P type semiconductors, for example. It may be advantageous if the ceramic and/or the dopant contains the element that will be ionized, and some of that element may be dislodged from the crystal structure. Additional ions may be drawn from the anode or the cathode, or from the atmospheric air if oxygen ions participate in the redox reactions.
The ionic conduction modes in ceramic electrolytes are very different from those present in aqueous or polymer electrolytes where no local crystal structure is present and where ions are released by means of electrolysis or simply pass through the fluid medium from the electrodes. In true solid electrolytes, as opposed to gels, both chemistry and mechanical forces play a role in ionic migration as does the phase of the local crystal structure.
