The length of the cantilever beam electrode is one of the important factors affecting the characteristics of piezoelectric vibration energy harvesting. The energy distribution function was proposed to describe the relationship between electric field energy and electrode ratio during the vibration energy harvesting

and the nature of the effect of electrode ratio on electrical characteristics was also explored. It is pointed out that the optimal electrode ratio of the rectangular and triangular cantilever beams to obtain the maximum power is between 50%~60%. In addition

the charge is redistributed with energy loss during vibration energy harvesting

and the energy loss is lowest at the optimal electrode and greater when the electrode ratio reaches 100%. Both the simulation and experiment results show that the optimal electrode ratio of the rectangular and triangular cantilever beams is in accordance with the optimal value obtained by the energy distribution function

and it is feasible to increase the output power by optimizing the electrode-length.