[1] M M TUMALA, A SALISU, Y B NMADU. Climate change fossil fuel prices: a GARCH-MIDAS analysis. Energy Economics, 106792(2023).

[2] Y L WU, Y L MA, H Y ZHENG et al. Piezoelectric materials for flexible and wearable electronics: a review. Materials & Design, 110164(2021).

[3] C CHEN, X WANG, Y WANG et al. Additive manufacturing of piezoelectric materials. Advanced Functional Materials, 2005141(2020).

[4] Q ZHENG, B J SHI, Z LI et al. Recent progress on piezoelectric and triboelectric energy harvesters in biomedical systems. Advanced Science, 1700029(2017).

[5] A MEGDICH, M HABIBI, L LAPERRIERE et al. A review on 3D printed piezoelectric energy harvesters: materials, 3D printing techniques, and applications. Materials Today Communications, 105541(2023).

[6] K BICY, A B GUEYE, D ROUXEL et al. Lithium-ion battery separators based on electrospun PVDF: a review. Surfaces and Interfaces, 101977(2022).

[7] J E LEE, Y E SHIN, G H LEE et al. Polyvinylidene fluoride (PVDF)/cellulose nanocrystal (CNC) nanocomposite fiber and triboelectric textile sensors. Composites Part B: Engineering, 109098(2021).

[8] S RIBEIRO, R M MEIRA, D M CORREIA et al. Silica nanoparticles surface charge modulation of the electroactive phase content and physical-chemical properties of poly(vinylidene fluoride) nanocomposites. Composites Part B: Engineering, 107786(2020).

[9] N D K TU, M S NOH, Y KO et al. Enhanced electromechanical performance of P(VDF-TrFE-CTFE) thin films hybridized with highly dispersed carbon blacks. Composites Part B: Engineering, 133(2018).

[10] K JEONG, D H KIM, Y S CHUNG et al. Effect of processing parameters of the continuous wet spinning system on the crystal phase of PVDF fibers. Journal of Applied Polymer Science, 45712(2017).

[11] S SHARAFKHANI, M KOKABI. High performance flexible actuator: PVDF nanofibers incorporated with axially aligned carbon nanotubes. Composites Part B: Engineering, 109060(2021).

[12] J CHEN, C AYRANCI, T TANG. Piezoelectric performance of electrospun PVDF and PVDF composite fibers: a review and machine learning-based analysis. Materials Today Chemistry, 101571(2023).

[13] Y WANG, D LEI, L K WU et al. Effects of stretching on phase transformation of PVDF and its copolymers: a review. Open Physics, 20220255(2023).

[14] S BARRAU, A FERRI, A DACOSTA et al. Nanoscale investigations of α- and γ-crystal phases in PVDF-based nanocomposites. ACS Applied Materials & Interfaces, 13092(2018).

[15] L JIN, S Y MA, W L DENG et al. Polarization-free high- crystallization β-PVDF piezoelectric nanogenerator toward self- powered 3D acceleration sensor. Nano Energy, 632(2018).

[16] S WANG, H Q SHAO, Y LIU et al. Boosting piezoelectric response of PVDF-TrFE via MXene for self-powered linear pressure sensor. Composites Science and Technology, 108600(2021).

[17] P YADAV, T D RAJU, S BADHULIKA. Self-poled hBN-PVDF nanofiber mat-based low-cost, ultrahigh-performance piezoelectric nanogenerator for biomechanical energy harvesting. ACS Applied Energy Materials, 1970(2020).

[18] F KHAN, T KOWALCHIK, S ROUNDY et al. Stretching-induced phase transitions in barium titanate-poly(vinylidene fluoride) flexible composite piezoelectric films. Scripta Materialia, 64(2021).

[19] A GEBREKRSTOS, G MADRAS, S BOSE. Journey of electroactive β-polymorph of poly(vinylidenefluoride) from crystal growth to design to applications. Crystal Growth & Design, 5441(2019).

[20] L J LU, W Q DING, J Q LIU et al. Flexible PVDF based piezoelectric nanogenerators. Nano Energy, 105251(2020).

[21] L YANG, H WANG, S P FANG et al. Research progress on energy storage performance enhancement strategies for polyvinylidene fluoride based composites. Journal of Alloys and Compounds, 170831(2023).

[22] H LI, H SONG, M J LONG et al. Mortise-tenon joint structured hydrophobic surface-functionalized barium titanate/polyvinylidene fluoride nanocomposites for printed self-powered wearable sensors. Nanoscale, 2542(2021).

[23] C WANG, C DONG, W PENG et al. Research progress of lead-free piezoelectric ceramics. China Ceramics, 1(2017).

[24] X Y GAO, J G WU, Y YU et al. Giant piezoelectric coefficients in relaxor piezoelectric ceramic PNN-PZT for vibration energy harvesting. Advanced Functional Materials, 1706895(2018).

[25] K LIU, C SUN, Y S SHI et al. Current status and prospect of additive manufacturing piezoceramics. Journal of Inorganic Materials, 278(2022).

[26] M PEDDIGARI, J H PARK, J H HAN et al. Flexible self- charging, ultrafast, high-power-density ceramic capacitor system. ACS Energy Letters, 1383(2021).

[27] Y ZHANG, C K JEONG, T N YANG et al. Bioinspired elastic piezoelectric composites for high-performance mechanical energy harvesting. Journal of Materials Chemistry A, 14546(2018).

[28] W X GAO, L YOU, Y J WANG et al. Flexible PbZr_0.52Ti_0.48O₃ capacitors with giant piezoelectric response and dielectric tunability. Advanced Electronic Materials, 1600542(2017).

[29] Z ZENG, L L GAI, X WANG et al. A plastic-composite-plastic structure high performance flexible energy harvester based on PIN-PMN-PT single crystal/epoxy 2-2 composite. Applied Physics Letters, 103501(2017).

[30] H KIM, D C NGUYEN, T T LUU et al. Recent advances in functional fiber-based wearable triboelectric nanogenerators. Nanomaterials, 2718(2023).

[31] C YANG, S P SONG, F CHEN et al. Fabrication of PVDF/ BaTiO₃/CNT piezoelectric energy harvesters with bionic balsa wood structures through 3D printing and supercritical carbon dioxide foaming. ACS Applied Materials & Interfaces, 41723(2021).

[32] L SONG, R X DAI, Y J LI et al. Polyvinylidene fluoride energy harvester with boosting piezoelectric performance through 3D printed biomimetic bone structures. ACS Sustainable Chemistry & Engineering, 7561(2021).

[33] Z H WANG, J CHENG, R C HU et al. An approach combining additive manufacturing and dielectrophoresis for 3D-structured flexible lead-free piezoelectric composites for electromechanical energy conversion. Journal of Materials Chemistry A, 26767(2021).

[34] Y HUAN, X S ZHANG, J A SONG et al. High-performance piezoelectric composite nanogenerator based on Ag/(K, Na)NbO₃ heterostructure. Nano Energy, 62(2018).

[35] H R PEI, S H SHI, Y H CHEN et al. Combining solid state shear milling and FFF 3D-printing strategy to fabricate high-performance biomimetic wearable fish-scale PVDF-based piezoelectric energy harvesters. ACS Applied Materials & Interfaces, 15346(2022).

[36] N P SORIMPUK, W H CHOONG, B L CHUA. Thermoforming characteristics of PLA/TPU multi-material specimens fabricated with fused deposition modelling under different temperatures. Polymers, 4304(2022).

[37] X G LIU, Y H SHANG, J H ZHANG et al. Ionic liquid assisted 3D printing of self-polarized β-PVDF for flexible piezoelectric energy harvesting. ACS Applied Materials & Interfaces, 14347(2021).

[38] H IKRAM, A ALRASHID, M KOC. Additive manufacturing of smart polymeric composites: literature review and future perspectives. Polymer Composites, 6355(2022).

[39] Z H WANG, X T YUAN, J K YANG et al. 3D-printed flexible, Ag-coated PNN-PZT ceramic-polymer grid-composite for electromechanical energy conversion. Nano Energy, 104737(2020).

[40] F CHEN, C YANG, Z M AN et al. Direct-ink-writing of multistage-pore structured energy collector with ultrahigh ceramic content and toughness. Materials & Design, 110652(2022).

[41] C HAN, L R HE, Q WANG et al. Solvent-exchange-assisted 3D printing of self-polarized high β-PVDF for advanced piezoelectric energy harvesting. ACS Applied Electronic Materials, 3125(2022).

[42] T SIPONKOSKI, M NELO, H JANTUNEN et al. A printable P(VDF-TrFE)-PZT composite with very high piezoelectric coefficient. Applied Materials Today, 100696(2020).

[43] S BODKHE, G TURCOT, F P GOSSELIN et al. One-step solvent evaporation-assisted 3D printing of piezoelectric PVDF nanocomposite structures. ACS Applied Materials & Interfaces, 20833(2017).

[44] R W TU, E SPRAGUE, H A SODANO et al. Precipitation-printed high-β phase poly(vinylidene fluoride) for energy harvesting. ACS Applied Materials & Interfaces, 58072(2020).

[45] A G TABRIZ, H KUOFIE, J SCOBLE et al. Selective laser sintering for printing pharmaceutical dosage forms. Journal of Drug Delivery Science and Technology, 104699(2023).

[46] S P SONG, Y HAN, Y J LI et al. 3D printed piezoelectric porous structure with enhanced output performance and stress-electricity response for road energy harvesting. Additive Manufacturing, 103625(2023).

[47] Z X LOW, Y T CHUA, B M RAY et al. Perspective on 3D printing of separation membranes and comparison to related unconventional fabrication techniques. Journal of Membrane Science, 596(2017).

[48] H C LIU, S MUKHERJEE, Y LIU et al. Recent studies on electrospinning preparation of patterned, core-shell, and aligned scaffolds. Journal of Applied Polymer Science, 45670(2018).

[49] A D WANG, J H LIU, C K SHAO et al. Electro-assisted 3D printing multi-layer PVDF/CaCl₂ composite films and sensors. Coatings, 820(2022).

[50] H C CUI, R HENSLEIGH, D S YAO et al. Three-dimensional printing of piezoelectric materials with designed anisotropy and directional response. Nature Materials, 234(2019).

[51] J H FEI, Y J RONG, L S ZHU et al. Progress in photocurable 3D printing of photosensitive polyurethane: a review. Macromolecular Rapid Communications, 2300211(2023).

[52] A SMIRNOV, S CHUGUNOV, A KHOLODKOVA et al. Progress and challenges of 3D-printing technologies in the manufacturing of piezoceramics. Ceramics International, 10478(2021).

[53] M ALIQUE, A MOYA, M KREUZER et al. Controlled poling of a fully printed piezoelectric PVDF-TrFE device as a multifunctional platform with inkjet-printed silver electrodes. Journal of Materials Chemistry C, 11555(2022).

[54] H LI, R H LI, X T FANG et al. 3D printed flexible triboelectric nanogenerator with viscoelastic inks for mechanical energy harvesting. Nano Energy, 447(2019).

[55] M H CHUNG, S YOO, H J KIM et al. Enhanced output performance on LbL multilayer PVDF-TrFE piezoelectric films for charging supercapacitor. Scientific Reports, 6581(2019).

[56] H LEE, B CHOI. A multilayer PVDF composite cantilever in the Helmholtz resonator for energy harvesting from sound pressure. Smart Materials and Strutures, 115025(2013).

[57] W S JUNG, M J LEE, M G KANG et al. Powerful curved piezoelectric generator for wearable applications. Nano Energy, 174(2015).

[58] X T YUAN, X Y GAO, J K YANG et al. The large piezoelectricity and high power density of a 3D-printed multilayer copolymer in a rugby ball-structured mechanical energy harvester. Energy & Environmental Science, 152(2020).

[59] T BHATTA, P MAHARJAN, H O CHO et al. High-performance triboelectric nanogenerator based on Mxene functionalized polyvinylidene fluoride composite nanofibers. Nano Energy, 105670(2021).

[60] Y G KIM, K T KIM, S C PARK et al. Enhanced poling efficiency via a maximized organic-inorganic interfacial effect for water droplet-driven energy harvesting. Nano Energy, 107238(2022).

[61] Q F ZHENG, H L ZHANG, H Y MI et al. High-performance flexible piezoelectric nanogenerators consisting of porous cellulose nanofibril (CNF)/poly(dimethylsiloxane) (PDMS) aerogel films. Nano Energy, 504(2016).

[62] A YAN, X T YUAN, Z M LI et al. 3D-printed flexible, layered ceramic-polymer composite grid with integrated structural-self- sensing function. Sensors and Actuators A: Physical, 113187(2021).

[63] X T YUAN, X Y GAO, X Y SHEN et al. A 3D-printed, alternatively tilt-polarized PVDF-TrFE polymer with enhanced piezoelectric effect for self-powered sensor application. Nano Energy, 105985(2021).

[64] Y LIU, L B DING, L DAI et al. All-ceramic flexible piezoelectric energy harvester. Advanced Functional Materials, 2209297(2022).

[65] X R ZHOU, K PARIDA, O HALEVI et al. All 3D-printed stretchable piezoelectric nanogenerator with non-protruding kirigami structure. Nano Energy, 104676(2020).

[66] H G TIAN, X B SHAN, H WANG et al. Enhanced piezoelectric energy harvesting performance using trailing-edge flap. Ocean Engineering, 115443(2023).

[67] H R PEI, Y P XIE, Y XIONG et al. A novel polarization free 3D printing strategy for fabrication of poly(vinylidene fluoride) based nanocomposite piezoelectric energy harvester. Composites Part B: Engineering, 109312(2021).

[68] F CHEN, Z M AN, Y H CHEN et al. Multi-material 3D printing of piezoelectric and triboelectric integrated nanogenerators with voxel structure. Chemical Engineering Journal, 144770(2023).

[69] O Y PAWAR, S LIM. 3D-Printed piezoelectric nanogenerator with aligned graphitic carbon nitrate nanosheets for enhancing piezoelectric performance. Journal of Colloid and Interface Science, 868(2023).

[70] C F CHEN, F X CAI, Y ZHU et al. 3D printing of electroactive PVDF thin films with high β-phase content. Smart Materials and Structures, 065017(2019).

[71] S P SONG, Y J LI, Q WANG et al. Boosting piezoelectric performance with a new selective laser sintering 3D printable PVDF/graphene nanocomposite. Composites Part A: Applied Science and Manufacturing, 106452(2021).

[72] C J SHUAI, G F LIU, Y W YANG et al. A strawberry-like Ag- decorated barium titanate enhances piezoelectric and antibacterial activities of polymer scaffold. Nano Energy, 104825(2020).

[73] F W QI, Z C ZENG, J YAO et al. Constructing core-shell structured BaTiO₃ carbon boosts piezoelectric activity and cell response of polymer scaffolds. Biomaterials Advances, 112129(2021).

[74] J F LIU, Y H SHANG, Z Z SHAO et al. Three-dimensional printing to translate simulation to architecting for three-dimensional high performance piezoelectric energy harvester. Industrial & Engineering Chemistry Research, 433(2021).

[75] X G LIU, Y H SHANG, J F LIU et al. 3D printing-enabled in-situ orientation of BaTi₂O₅ nanorods in β-PVDF for high-efficiency piezoelectric energy harvesters. ACS Applied Materials & Interfaces, 13361(2022).

[76] L R HE, J LU, C HAN et al. Electrohydrodynamic pulling consolidated high-efficiency 3D printing to architect unusual self-polarized β-PVDF arrays for advanced piezoelectric sensing. Small, 2200114(2022).

[77] X G LIU, J F LIU, L R HE et al. 3D printed piezoelectric regulable cells with customized electromechanical response distribution for intelligent sensing. Advanced Functional Materials, 2201274(2022).

[78] H KIM, F TORRES, Y Y WU et al. Integrated 3D printing and corona poling process of PVDF piezoelectric films for pressure sensor application. Smart Materials and Structures, 085027(2017).

[79] A ZASZCZYŃSKA, A GRADYS, P SAJKIEWICZ et al. Progress in the applications of smart piezoelectric materials for medical devices. Polymers, 2754(2020).

[80] B MAAMER, A BOUGHAMOURA, A M R F ELBAB et al. A review on design improvements and techniques for mechanical energy harvesting using piezoelectric and electromagnetic schemes. Energy Conversion and Management, 111973(2019).

[81] K TAKAHASHI, K ONO, H ARAI et al. Detection of pathologic heart murmurs using a piezoelectric sensor. Sensors, 1376(2021).

[82] M SAWANE, M PRASAD. MEMS piezoelectric sensor for self- powered devices: a review. Materials Science in Semiconductor Processing, 107324(2023).

[83] X YANG, J S MENG, Y WANG et al. Novel formation of Bi@BiFe-glycolate hollow spheres and their conversion into Bi₂O₃/BiFeO₃ composite hollow spheres with enhanced activity and durability in visible photocatalysis. New Journal of Chemistry, 10697(2018).

[84] S AZIMI, A ABOLHASANI, S M MOOSAVI et al. Development of a vehicle passage sensor based on a PVDF nanogenerator. ACS Applied Electronic Materials, 4689(2021).

[85] D S YAO, H C CUI, R HENSLEIGH et al. Achieving the upper bound of piezoelectric response in tunable, wearable 3D printed nanocomposites. Advanced Functional Materials, 1903866(2019).

[86] V CACUCCIOLO, J SHINTAKE, Y KUWAJIMA et al. Stretchable pumps for soft machines. Nature, 516(2019).

[87] T YANG, H PAN, G TIAN et al. Hierarchically structured PVDF/ZnO core-shell nanofibers for self-powered physiological monitoring electronics. Nano Energy, 104706(2020).

[88] X W LIANG, T ZHAO, W JIANG et al. Highly transparent triboelectric nanogenerator utilizing in-situ chemically welded silver nanowire network as electrode for mechanical energy harvesting and body motion monitoring. Nano Energy, 508(2019).

[89] A GAUR, S TIWARI, C KUMAR et al. Flexible, lead-free nanogenerators using poly(vinylidene fluoride) nanocomposites. Energy & Fuels, 6239(2020).

[90] H X SU, X B WANG, C Y LI et al. Enhanced energy harvesting ability of polydimethylsiloxane-BaTiO₃-based flexible piezoelectric nanogenerator for tactile imitation application. Nano Energy, 105809(2021).

[91] F W QI, N CHEN, Q WANG. Preparation of PA11/BaTiO₃nanocomposite powders with improved processability, dielectric and piezoelectric properties for use in selectivelaser sintering. Materials & Design, 135(2017).

[92] W L DENG, T YANG, L JIN et al. Cowpea-structured PVDF/ZnO nanofibers based flexible self-powered piezoelectric bending motion sensor towards remote control of gestures. Nano Energy, 516(2019).

[93] Q L HUA, J L SUN, H T LIU et al. Skin-inspired highly stretchable and conformable matrix networks for multifunctional sensing. Nature Communications, 244(2018).

[94] Y CHENG, Y XU, Y QIAN et al. 3D structured self-powered PVDF/PCL scaffolds for peripheral nerve regeneration. Nano Energy, 104411(2020).

[95] J C LIANG, H J ZENG, L QIAO et al. 3D Printed piezoelectric wound dressing with dual piezoelectric response models for scar- prevention wound healing. ACS Applied Materials & Interfaces, 30507(2022).