Fig. 5: In-vitro and on-body charging performance of the wearable bioenergy microgrid system.

a In-vitro charging curves of the individual and integrated harvester with (i)-(iii) 1 Hz frequency and 10 mM lactate; (iv)-(vi) 1.5 Hz frequency and 10 mM lactate; and (vii)-(ix) 1.5 Hz and 15 mM lactate for the TEG modules and the BFC modules, which simulate three representative phases: starting ((i), (iv), and (vii)), exercising((ii), (v), and (viii)) and ending((iii), (vi), and (ix)) of an activity session. b Photo illustration of the on-body testing arrangement. c On-body charging of a 150 μF SC using the individual BFC or TEG module alone, and with both modules combined, in a 10-min exercise session followed by a 20-min resting. d On-body charging of capacitors from SCs with (i) 75 μF, (ii) 150 μF, and (iii) 300 μF from 0 V in a 30-min exercise session to represent the charging of the system including the cold-starting phase of the voltage-booster. During the 30-min period, movement stops once the SC if fully charged to 5.1 V.