Fig.1. Classification of various energy types and methods of using electrical energy 17

Fig.2. Energy consumption structure (a) changes in global primary energy consumption, (b) renewable energy distribution of developing countries 18

Fig.3. Lithium mines and polluted sulfuric acid waste reservoir 19

Fig.4. Renewable energy and ESS market 20

Fig.5. Pattern fabrication process (a) photolithography, (b) reactive ion etching 22

Fig.6. Inkjet process (a) schematic of process, (b) fabricated nozzle hole, (c) printed pattern 23

Fig.7. Roll-to-roll process (a) schematic of process, (b) picture of printed pattern, (c) SEM image of printed pattern 24

Fig.8. Imprinting process (a) schematic of process using various curing methodes, (b) 3D stacked... 25

Fig.9. Laser process (a) cutting y, (b) welding, (c) laser assisted machining, (d) water jet guided laser 26

Fig.10. Mechanism of nanoparticle laser sintering (a) photo thermal sintering,(b) photo thermochemical sintering 27

Fig.11. Fabrication method for porous structure using a laser (a) multi photon absorption, (b) mechanism of growth sintering, (c) fabrication of... 28

Fig.12. Waste energy devices and market size 29

Fig.13. Environmental pollution caused by waste energy devices 30

Fig.14. Cause of death by environmental factors 31

Fig.15. Resource recovery process of waste energy device 32

Fig.16. Concept of natural device 33

Fig.17. Concept of natural energy device fabricated using stone and laser material interface 35

Fig.18. Characteristics and various application fields of supercapacitors 37

Fig.19. Classification and structure of supercapacitors 39

Fig.20. Structure for the enhanced performance of supercapacitors 41

Fig.21. Characteristics of transition metal oxides (a) theoretical capacitance (b) voltage range 42

Fig.22. Research trends of supercapacitors (a) various shapes, (b) high performance materials, (c) application of functionality, (d) new materials 43

Fig.23. 3D porous structure fabrication method (a) molten gas injection method, (b) particulate leaching method, (c) 3D printing, (d) Laser induced forward transfer 45

Fig.24. Research object 46

Fig.25. Natural MSC stone design 47

Fig.26. Mechanism of ERS process for 3D porous Cu structure 48

Fig.27. Multi stage photo thermochemical reaction 49

Fig.28. 3D porous Cu patterning using ERS process 49

Fig.29. Residual CuO spray cleaning 49

Fig.30. Schematics of 3D porous Cu pattern fabrication process 51

Fig.31. Schematics of natural MSC stone fabrication process 51

Fig.32. Structural change of 3D porous Cu dependent on residual solvent amount 53

Fig.33. Pattern edge uniformity dependent on residual solvent amount 53

Fig.34. Comparison schematics of surface area of simplified structure (a) 2D porous, (b) 3D porous 53

Fig.35. SEM images of the fabricated 3D porous Cu (a) low magnification surface, (b) high magnification surface, (c) cross section 54

Fig.36. High magnification SEM images of multiscale structures of 3D porous Cu (a) surface, (b) cross section 54

Fig.37. XRD data of marble, CuO and reduced Cu 55

Fig.38. Resistivity and surface area according to patterning speed 57

Fig.39. Extracted surface area images according to patterning speed 57

Fig.40. Surface SEM images according to patterning speed 58

Fig.41. Electrode peeled off at 12 mm/s patterning speed 58

Fig.42. Corss section SEM images according to patterning speed 59

Fig.43. Tilted SEM image of a biscuit 3D porous Cu 59

Fig.44. Roughness of marble polished with different sandpaper 60

Fig.45. 3D porous Cu patterns fabricated on marble with different roughness 61

Fig.46. SEM and TEM images of electrochemical deposited sponge structure of Mn₃O₄ 63

Fig.47. SEM and TEM images of electrochemical deposited coral structure of Fe₃O₄ 64

Fig.48. Structural change with different TMO loading mass 64

Fig.49. XPS data of 3D porous Cu 66

Fig.50. XPS data of sponge structure of Mn₃O₄ 66

Fig.51. XPS data of coral structure of Fe₃O₄ 66

Fig.52. FTIR data of 3D porous Cu, Mn₃O₄, Fe₃O₄ 67

Fig.53. 3D porous Cu patterned natural MSC stone 68

Fig.54. TMO electrochemical deposited natural MSC stone (a) Picture of device, (b) microscopy image (c) SEM image 68

Fig.55. EDS mapping image of Cu, Fe, Mn 69

Fig.56. Cell configuration and nyquist plot for EIS 70

Fig.57. CV curves of three working principles 72

Fig.58. CV curves graph at different voltage ranges 72

Fig.59. CV curves graph at different TMO mass 73

Fig.60. CV curves graph at different scan rate 73

Fig.61. Areal capacitance change at different scan rate 74

Fig.62. GCD curves graph at different current density 74

Fig.63. Nyquist plot of natural MSC stone measured by EIS 75

Fig.64. Capacitance retention of natural MSC stone 76

Fig.65. Ragone plot of natural MSC stone 77

Fig.66. Natural MSC modules in series connection 78

Fig.67. CV curve graph of Natural MSC modules in series connection 79

Fig.68. GCD curve graph of Natural MSC modules in series connection 79

Fig.69. Natural MSC modules in parallel connection 79

Fig.70. CV curve graph of natural MSC modules in parallel connection 80

Fig.71. GCD curve graph of natural MSC modules in parallel connection 80

Fig.72. Designed large scale of natural MSC stone 81

Fig.73. Plug-in method for large area easy connection 81

Fig.74. Large scale connected natural MSC module 81

Fig.75. Mechanical stability test of natural MSC module 82

Fig.76. Capacitance stability under repeated shock 82

Fig.77. Natural MSC stone eco-recycleing process after use 83

Fig.78. Waste component and weight comparison 84

Fig.79. Eco-friendly energy storage platform with natural MSC module 86

Fig.80. Characteristics of TENG and harvestable energy 88

Fig.81. Roadmap of TENG technology 89

Fig.82. Type of TENG working mode 90

Fig.83. Working mechanism of single electrode rain cell 92

Fig.84. Positive and negative charge affinity materials 93

Fig.85. Methods for improving the performance of TENG 96

Fig.86. Representative structure of rain cell (a) droplet driven, (b) single electrode, (c) bi-electrode, (d) S-TIGER 97

Fig.87. Hybrid devices integrated with S-TIGER (a) piezoelectric, (b) solar cell, (c) streaming power generation, (d) applied additional layer 98

Fig.88. Porous Al fabrication method (a) shoot penning, (b) high temperature imprinting, (c) etching, (d) anodic aluminum oxide 100

Fig.89. Defects in Al thermal process 101

Fig.90. Research object 102

Fig.91. Natural rain stone design 103

Fig.92. Mechanism of IPHC process for porous Al structure 105

Fig.93. Mechanism of hydrophobic clustering 105

Fig.94. Laser induced marangoni effect (a) laser power, (b) random scattering, (c) droplet movement 105

Fig.95. Schematics of porous Al fabrication process 107

Fig.96. Schematics of rain stone fabrication process 107

Fig.97. Size distribution frequency of Al particle 108

Fig.98. Oxide volume ratio of different Al particle size 108

Fig.99. Structural ch/different laser power 110

Fig.100. Structural change of porous Al at the fixed pulse width of 200 ns and varying repetition rate 111

Fig.101. Structural change of porous Al at the fixed pulse width of 100 ns and varying repetition rate 111

Fig.102. Characteristic of pulse laser parameters (a) pulse energy and temperature, (b) repetition rate and temperature, (c) pulse energy and penetration depth, (d) pulse... 114

Fig.103. Change of laser penetration depth according to pulse width 115

Fig.104. Structural change of porous Al with repetition rate 115

Fig.105. Sheet resistance and surface area change under different pulse width 116

Fig.106. Extracted surface area images at different repetition rate 117

Fig.107. EDS data of porous Al 118

Fig.108. XRD data of marble, Al particle and sintered Al 118

Fig.109. Al electrode FPCB fabrication experiment steps (a) Al particle coating on PI film, (b) IPHC process, (c) residual Al particle cleaning 119

Fig.110. Al electrode FPCB fabricated on PI film (a) flat image, (b) bent image 119

Fig.111. Al electrode PCB fabricated on Glass 119

Fig.112. Comparison of thermal diffusion CW and pulse laser 120

Fig.113. Before and after etching image of Al electrode fabricated using CW laser and pulse laser 121

Fig.114. SEM Images of fabricated Al electrode at various speeds on PI film (a) 0.08 m/s, (b) 0.1 m/s (c) 0.12 m/s (d) 0.14 m/s 122

Fig.115. Electrical characteristics and line width of Al electrode fabricated at various speeds on PI film 123

Fig.116. High resolution Al electrode fabricated on PI film 123

Fig.117. FPCB bent with different radius 125

Fig.118. Resistance change with different radius 125

Fig.119. Change in resistance at the number of repeated bending 125

Fig.120. Demonstrated flexible micro heater 126

Fig.121. Adhesion test of fabricated PCB 126

Fig.122. Gravel-like structure fabricated by IPHC process 127

Fig.123. Roughness of marble substrate polished with sandpaper at different grit mesh 128

Fig.124. Fabricated porous Al patterns in different roughness marbles 129

Fig.125. Composition of natural rain stones matched with FET 131

Fig.126. Selected positively charged and negatively charged materials 131

Fig.127. Working mechanism of natural rain stone 131

Fig.128. Time-dimensional voltage characteristics according to the behavior of water droplet falling on natural rain stone 132

Fig.129. Designed natural rain stone 133

Fig.130. Defects in sheet formation at different pulse repetition rates 133

Fig.131. DIY raining simulation system 134

Fig.132. Voltage generation at different PDMS thicknesses 135

Fig.133. Image of different PDMS thicknesses 135

Fig.134. Voltage generation at different pulse repetition rates 137

Fig.135. Current generation at different pulse repetition rates 137

Fig.136. Surface area at different repetition rates 138

Fig.137. Performance enhancement mechanisms of natural rain stone 138

Fig.138. Voltage generation at different active layer area 139

Fig.139. Current generation at different active layer area 140

Fig.140. Fallen droplet spread area 140

Fig.141. Energy per unit area that generate in different areas 141

Fig.142. Voltage generation at different falling hight 142

Fig.143. Voltage generation at different droplet volume 142

Fig.144. Voltage generation at different falling frequency 143

Fig.145. Long time stability of natural rain stone 143

Fig.146. Voltage and current at different external resistances 144

Fig.147. Power and current density at different external resistances 145

Fig.148. Ragone plot of natural rain stone 145

Fig.149. Natural rain stone used as LED power source 146

Fig.150. Contact angle of natural rain stone 147

Fig.151. Cell array of natural rain stone 147

Fig.152. Voltage generation of each cell according to water drop movement 148

Fig.153. Mechanical stability (a) smashing test, (b) rubbing test 148

Fig.154. Schematic of hybrid system of solar cell and rain stone 149

Fig.155. Power density of hybrid system at various weather 149

Fig.156. Natural rain stone eco-recycleing process after use 150

Fig.157. Efficient repair method of natural rain stone and weight of waste 150

Fig.158. Natural rain stone applied eco-friendly energy generation platform 152