Diving–Surfacing Smart Locomotion Driven by a CO₂‐Forming Reaction, with Applications to Minigenerators

Abstract

Harvesting energy from environment has attracted increasing attention for its potential applications in fabricating minigenerator. However, most studies in the fabrication of mini‐ or nanogenerators are based on the concept of piezoelectricity or triboelectrification while few of the reports paid attention to the classical theory of Faraday's law. Herein, a pH responsive smart surface is combined with the reaction between CaCO3 and HCl to develop a new minigenerator, which can convert mechanical energy generated from the chemical reaction into electrical energy through cutting magnetic lines with moving conductive lines. The conductive lines are connected with a smart device consisting of a pH‐responsive cube, a hydrophobic cube, and a quartz cell window; the device can perform diving‐surfacing cycled motions with an intelligent initiation through the adjustment of the solution. The device can surface through gathering CO2 bubbles from the reaction between CaCO3 and HCl and dive by releasing the bubbles on the water/air interface. Moreover, the results demonstrate that the inert CO2 was nonhazardous to the smart surfaces, which is meaningful for durable electricity generation.

Electricity Generation through Light‐Responsive Diving–Surfacing Locomotion of a Functionally Cooperating Smart Device

“…Thus, the device requires a longer time to shift from surfacing to diving. Because the induced voltage appears at the points when surfacing and diving motions are shifted, the frequency between the appearance of negative and positive induced voltage decreases; meanwhile, with longer time for acceleration, the maximum velocity of the device also grows, which results in increased induced voltage according to the correlation of E = Blv ( E : induced voltage; B : magnetic induction intensity; l and v : size and velocity of the device) …”

Mini‐Generator Based on Reciprocating Vertical Motions Driven by Intracorporeal Energy

“…Thus, the device performed a regular diving/surfacing motion. Based on the voltage–time curve and the total resistance of the circuit, we calculated the energy conversion rate to be 8.11% when the frequency of the pressure switch between 40 and 0 mmHg was 0.5 Hz (calculation details in Section S3 in the Supporting Information), which was five orders of magnitude higher than reported values . The above results demonstrate that the as‐prepared mini‐generator functioned well in a model system in response to cyclic changes in ambient pressure.…”

“…The recently developed mini‐generators, which are based on self‐propulsion, especially vertical motion, may provide a feasible solution to the above problems. By applying a magnetic field to the repeated reciprocating motions of a conductor, an induced current can be obtained in a coil according to the classic Faraday's law of induction.…”

“…The key to fabricating such mini‐generators lies in realizing efficient vertical motions of either the conductors or the magnets, which requires energy input to reversibly change the density of the device. Previously, we used bubble‐generating chemical reactions as the energy resource and applied bubble‐collection/release processes to adjust device density; however, problems of relying on fuel input and a low energy conversion rate remain to be addressed for further practical uses . Herein, we have designed a mini‐generator system that uses the intracorporeal energy available in the human body , i.e., a constant pressure difference between systolic pressure and diastolic pressure, as a sustainable energy resource to propel vertical motions of a device.…”

Bubble‐Enabled Underwater Motion of a Light‐Driven Motor

“…These natural species inspires the design and fabrication of the functional motor and the control over the underwater motions by different external stimuli. Shi and co‐workers has demonstrated a chemical approach that uses gas bubbles such as O 2 , CO 2 , and H 2 generated from redox chemical reaction to provide the propulsive force for the underwater motion of smart metal foam devices . Meanwhile, Sanchez and co‐workers presented a controllable way of studying chemotactic behavior of two families of artificial catalytic micromotors (tubular microjets and Janus particles), known to be driven by hydrogen peroxide, which is used both as a fuel and as chemical attractant.…”