Electrochemistry is playing very important role of energy storage, sensing, manufacturing systems, etc. In contrast, it has gotten less attention in the field of energy harvesting. However, electrochemical system has lots of potential of various energy harvesting applications from large scale to miniaturized scale because of its cost-effective electrode materials and simple configuration. In this talk, I will discuss how electrochemical system can be applied various energy harvesting systems with a mechanical perspective. In the first part of the talk, the electrochemical thermodynamic cycle for thermal energy harvesting will be introduced. By utilizing novel electrode materials, this system can achieve very high efficiencies at low temperature ranges. In the second part of the talk, we suggest an electrochemical kinetic energy harvesting using selective ion sweeping on the supercapacitor electrode and ion hosting battery electrode. Shaking a hybrid cell consisting of supercapacitor electrode and battery electrode induces ion sweeping on supercapacitor by the electrolyte flow inside the cell and generates electricity. This method can obtain continuous current with slow decaying, i.e.) non-peak energy, which can be efficiently used in low frequency kinetic energy harvesting.