Fig. 9.

a Schematic showing the design and structure of the self-charging power cell. This structure is sealed in stainless steel 2016-coin-type cells, as shown in the inset. On adhering a power cell to the bottom of a shoe, the compressive stress generated by walking can be converted and stored directly by SCPC. Reproduced with permission [44]. Copyright 2012, American Chemical Society. b Schematic structure of a SCPC with a PVDF–PZT nanocomposite film as a piezo-separator for charge storage. Photograph of PVDF–PZT nanocomposite film. Adhering an SCPC underneath the button of a calculator, the mechanical energy generated by pressing the button can be converted and directly stored by the SCPC. Reproduced with permission [181]. Copyright 2014, IOP Publishing Ltd