Laser-induced graphene (LIG) has
aroused a wide range
of research
interests ranging from micro-nano energy devices to the Internet of
Things (IoT). Nevertheless, the non-degradability of most-used synthetic
polymer carbon sources poses a serious threat to the environment.
In this work, ecofriendly chitosan-based derivatives, including carboxymethyl
chitosan (CMCS), chitosan oligosaccharide, and chitosan hydrochloride,
are successfully converted into LIGs for the first time via a convenient
one-step CO2 laser engraving at ambient air. The obtained
LIGs are characterized by a three-dimensional hierarchical porous
structure and exhibit good sheet conductivity. The consecutive carbonization
and graphitization mechanism of target precursors induced by laser
heat accumulation is also deeply discussed. Besides, based on a mechanically
reliable LIG/CMCS composite film and tribo-negative acrylic/polyimide
anti-layers, two contact-separation mode triboelectric nanogenerators
are built and their power densities range from 1.44 to 2.48 mW cm–2. These devices with long cycle life can be used for
low-frequency mechanical energy harvesting and commercial capacitance
charging, which could be potentially applied in the wireless sensor
network nodes. Such a family of chitosan derivatives paves a new route
for LIG synthesis and provides new ideas for ecofriendly LIG electronics.