How does the dielectric constant of a material affect its charge retention capability?

The dielectric constant of a material directly affects its charge retention capability by determining its ability to store electrical energy. A higher dielectric constant allows the material to store more electrical energy for a given voltage. The stored energy is related to the charge (Q), voltage (V), and capacitance (C) by the equation E = 1/2 C V^2, where capacitance is proportional to the dielectric constant (C = εA/d, where ε is the permittivity, which is related to the dielectric constant). A higher dielectric constant means a higher capacitance, and thus a greater amount of energy can be stored for a given voltage. This translates to a higher charge density and a better ability to retain the triboelectric charges generated in a TENG. Materials with low dielectric constants have a limited capacity to store charge, leading to rapid charge dissipation. For example, materials like high-k ceramics (high dielectric constant) are better at retaining charge compared to air or vacuum (low dielectric constant) when used in TENGs.