Research Article

Energy Conversion in Protocells with Natural Nanoconductors

Table 1

The calculated electrogenic performance of three cell types: the natural electrocyte, and the optimized protocell with AC output, and the optimized protocell with DC output.

CellsElectrocyteOptimized AC protocellDC protocell

Maximum power density (W·kg−1)3.284.1912.6
Maximum energy density (W·h·kg−1)3.28*4.19*1.92
Maximum energy conversion efficiency (%)14.719.748

*: The energy densities of these two cells are estimated based on simulations of one hour continuous output; but the actual energy densities may be even larger with enough ATP supplied; Electrophorus electricus can generate low-level action potentials for hours without any sign of exhaustion [80, 81].
†: The protocell designed for DC output can reach an energy conversion efficiency of 48%; but this configuration has impractically low energy density (  J·m−3  W·h·kg−1). This protocell designed for maximum energy density (  J·m−3, i.e., 1.92 W·h·kg−1) has an energy conversion efficiency of 10%.