Scalable piezoelectrochemical energy harvesting via Li-ion battery-based DEECs with laser-patterned electrodes

Piezoelectrochemical energy harvesting converts mechanical compression into electrical output through stress-coupled electrochemistry in lithium-ion systems. Here, we study lithium-ion battery-based distributed embedded energy converters (DEECs) as unit cells in DEEC-Tec metamaterials and examine how interconnection topology and electrode microarchitecture affect performance under 10 MPa loading. For commercial pouch cells, harvested energy increased from 153 to 395 μJ/cycle in series and from 101 to 204 μJ/cycle in parallel as the number of units increased from one to four, while a hybrid series-parallel network delivered the best performance (501 μJ/cycle; 16.73 nW/Ah). For laboratory-fabricated cells, laser-patterned electrodes improved harvested energy and capacity-normalized output by 84.5% despite an 18%-19% capacity loss. Electrochemical impedance spectroscopy showed 89.8% lower solid-electrolyte interphase resistance, 18.1% lower charge-transfer resistance, and 77.7% lower total resistance. These results show that topology and electrode microstructure can jointly improve scalable low-frequency piezoelectrochemical energy harvesting.