Moist-Induced Electricity Generation by Electrospun Cellulose Acetate Membranes with Optimized Porous Structures

Abstract

Harvesting energy from moist in the atmosphere has recently been demonstrated as an effective manner for a portable power supply to meet the ever-increasing demands of energy consumption. Porous materials are shown to have great potential in moist-induced electricity generation. Herein, we report moist-induced electricity generation by electrospun cellulose acetate (CA) membranes with optimized porous structures. We show that the pore size and porosity of CA membranes can be readily tuned via a facile compression and annealing process, and the effect of pore features on the output voltages can thus be investigated systematically. We find that, at a relatively high porosity, the electricity-generation performance can be further enhanced by constructing a smaller pore to form more nanochannels. Porous CA membranes, with an optimized porosity of 52.6% and a pore diameter less than 250 nm, are prepared to construct moist-induced electricity generators, which can be applied as breath sensors and can power up calculator operation. The current study provides insights for the construction of porous materials with different pore characteristics for moist-induced electricity generation, especially in the exploration of more efficient and low-cost porous materials for large-scale practical application of the portable power supply.

Water‐Enabled Electricity Generation: A Perspective

“…Because carbon‐based materials have a high conversion efficiency, they account for the majority of the active materials used in water‐enabled electricity generation systems, with the focus being on graphene‐based materials, [ 15,22,24,36–39,44–46,48,55,66,68–81 ] CNPs and carbon nanofibers (CNFs), [ 13,14,16,25,53,64,67,82–91 ] polymers, [ 23,31,38,66,83,89,92–99 ] and biomaterials. [ 26,30,69,74,90,91,100–102 ] Solid oxide materials [ 10,12,13,19,20,54,64,103–106 ] are also favored as they are easily fabricated into an active layer and are stable even in harsh environments. Some other materials suitable for applications in WEEGs include Mg, [ 14,40 ] Si, [ 68,107 ] Ni‐Al, [ 65 ] Cu‐Zn [ 108 ] MoS 2 , [ 27 ] and glass fibers.…”

“…a) Distribution of materials used in applications. [ 10,12–16,19,20,22–27,30,31,33–40,44–48,53–55,64–80,82–108,117–123 ] b) Output voltage and power density for different materials. c) The output voltage and d) averaged voltage of single and integrated devices.…”

“…Biomaterials Biomaterials, including natural and synthesized materials, are attracting much attention as components in electronic devices as these materials are generally widely available, mechanically robust, biodegradable, and self-sustainable. [113] Biomaterials now used in the assembly of WEEGs include cellulose nanofibrils (NFs), [26,89] cellulose acetate (CA), [100] cotton fabric, [90] natural wood, [102] paper [85,101] and protein nanowires. [30] While these materials are intrinsically active in the generation of electricity, it has been found that it is often advantageous to combine different types of functional materials to improve overall performance.…”

Recent progress in cellulose-based electrospun nanofibers as multifunctional materials

“…Cellulose nanofibril also accelerated the stabilization process by reducing the required energy for the nitrile-based cleavage in the carbonization reaction. An interesting and novel work was reported by Lyu et al 66 , who utilized the porous structure of electrospun CA fabrics to construct moist-induced electricity generators. Hydroxyl and carbonyl groups of CA dissociated and formed negatively charged surfaces when the nanofibers were exposed to moist.…”

“…(b) Electricity generation based on the CA nanofiber with annealing time of 5 min in response to the change of RH (ΔRH = 85%). (c) Illustration of electrospun cellulose acetate nanofibers exposing to the moist flow (reprinted with permission 66 , ACS publishing).An interesting and novel work was reported by Lyu et al66 , who utilized the porous structure of electrospun CA fabrics to construct moist-induced electricity generators. Hydroxyl and carbonyl groups of CA dissociated and formed negatively charged surfaces when the nanofibers were exposed to moist.…”