polymer gels with tunable ionic seebeck coefficient for ultra-sensitive printed thermopiles - polymer gel
Measuring temperature and heat flow is important to regulate any physical, chemical and biological processes.
Conventional thermal power piles can provide accurate and stable temperature readings, but they are brittle inorganic materials based on low Seebeck coefficients, which are difficult to manufacture in large areas.
Recently, polymer electrolyte has been proposed for thermoelectric applications due to its large ion Seebeck coefficient, high elasticity and ease of manufacture.
However, the material reported so far has a positive Seebeck coefficient, which hinders the super
Sensitive ion thermoelectric reactor.
Here we report a "polar" ionic polymer gel with a large negative ion zebeck coefficient.
The latter can be adjusted from negative to positive by adjusting the gel composition.
We found ions-
The polymer matrix interaction is essential to control the symbol and size of the ion Seebeck coefficient.
Double polar gel can be easily screen printed to make large-
Low-cost regional equipment manufacturing.
Thermoelectric materials can convert heat directly into electrical signals and can be used for heat flow and temperature sensing.
These technologies are based on the Seebeck effect. e.
, Create a voltage on the material affected by the temperature gradient.
The voltage comes from the diffusion of the mobile charge carrier transmitted by heat flow.
The size of this phenomenon is different in different materials and can then be classified according to their Seebeck coefficients ().
Different from conductivity ()
Proportional to the concentration of the charge carrier, the Seebeck coefficient is usually reduced with the increase of the concentration of the charge carrier.
Therefore, in the insulator material with a large energy gap, it is likely that 1 MVK or higher Sebeck coefficient will be found.
However, the conductivity of the insulator is low (
Below 10 Ω cm)
Reliable thermal voltage measurements are challenging.
A special class of electronic insulators appeared in thermoelectric applications: electrolyte.
These materials are not electronic charge carriers, but ion charge carriers, which are heat diffusion by Soret effect at a temperature gradient.
Recently, several groups have reported the ultra-high value of the ion Seebeck coefficient in the electrolyte, reaching 10 mv, and their ion conductivity is large enough to ensure a simple thermal voltage measurement.
A major difference between the ion and the electronic thermoelectric material is that when the ion reaches the metal electrode, the ion cannot enter the external circuit.
Therefore, when operating at a constant temperature difference, the ion thermoelectric device does not generate constant power.
However, the thermal diffusion of ions creates a large constant voltage that can be used for heat flow sensing or temperature measurement.
Recent studies have also shown that ions accumulated at the electrode/electrolyte interface can be used for energy conversion applications.
In fact, the use of high-capacitance electrode materials, such as carbon nanotubes and conductive polymers, greatly increases the amount of charge that can be accumulated on the electrode/electrolyte interface, thus allowing charging of the super capacitor and battery.
Polymer electrolyte with a large zebeck coefficient has also aroused interest in new research directions, such as in thermal electronic circuits that utilize heat as input signals, and in supercells
Sensitive temperature sensors that compete with thermoelectric detectors. Polymer-
Base electrolyte is attractive because they are solid (or gels)
Rather than liquid, this is advantageous in the manufacture and use of ionic electronic devices.
One can foresee the possible application of this huge ion Seebeck coefficient in combination with other polymer electrolyte
Electrodiscoloration display, ion pump, ion bipolar diode, ion bipolar junction transistor, electrodiscoloration bipolar membrane diode and other devices.
Coefficient of ion Seebeck (
Will . . . . . . The electrolyte measurement of =/Delta is open-circuit thermovoltage ()
Induced on the material by a given temperature difference (Δ).
This is proportional to the difference in concentration distribution between Yin and Yang ions.
In turn, the concentration gradient of the Yin and Yang ions depends on
Diffusion coefficient, effective ion concentration (
Only ions that are dissolved)
Soret coefficient of ions.
Soret coefficient is a relatively complex parameter determined by the temperature dependence of the structural entropy, which is related to the interaction between ions and solvents along the thermal field.
Ions that increase the local order of the surrounding solvent molecules are called structural manufacturers (
And those that reduce local orders are named structural circuit breakers (
Modern theoretical modeling tools based on unstructured
Equilibrium molecular dynamics successfully calculated the Soret and Seebeck coefficients in simple atomic salts such as LiCl.
In contrast, there is no satisfactory theory for polymer electrolyte that can accurately describe or predict these coefficients.
The intuitive strategy of selecting an electrolyte with a large difference in the diffusion coefficient of Yin and Yang ions leads to a very large Seebeck value, which cannot be fully explained yet.
Examples include a solution of four positive ammonium nitrate in alcohol (+7u2009mVu2009K)
Ionic functional liquid polyethylene glycol (+11u2009mVu2009K)
Hydration of polystyrene sulfuric acid (+8u2009mVu2009K)
, Polystyrene sodium acetate (+4u2009mVu2009K)
And cellulose (+8. 4u2009mVu2009K).
It is worth noting that all of these huge Seebeck coefficients are positive, which means that the cation is more prone to heat diffusion than the anion (
Analogy with solid
We define these electrolyte as "p-type”).
However, effective thermoelectric modules depend on positive and negative thermoelectric legs (p-and n-legs).
Although it is reported that the negative Seebeck coefficient of the electrolyte conducting the electrochemical reaction on the electrode is about 1-2? Mvk (i. e.
Thermal Current effect), no “n-
To date, "type" ion thermoelectric materials based on pure Soret effect have been reported.
Therefore, in order to achieve a powerful technology based on the ion Seebeck effect, the development of "n-
"Type" polymer gel electrolyte with negative giant saebeck coefficient.
Here, we propose a "polar" polymer gel with a negative zebeck coefficient and demonstrate that the symbol and size of the zebeck coefficient can be controlled by adjusting the composition of the polymer matrix.
Gradient of pulse field (PFG)
Nuclear magnetic resonance (NMR)
The movement and interaction of ions were studied by means of spectra, Raman spectra and infrared spectra.
Finally, use "n-type” (negative )and “p-type” (positive )
Manufacture of ion thermoelectric modules by printing technology and display its polymer gel as the temperature sensing function of the ion thermoelectric stack.