We studied the local structure and properties of six-fold coordinated silicon(Si[6]) in BaOSiO2-P2O5 glasses. Nuclear magnetic resonance(NMR) and Raman spectroscopy revealed the existence of sixfold coordinated silico...We studied the local structure and properties of six-fold coordinated silicon(Si[6]) in BaOSiO2-P2O5 glasses. Nuclear magnetic resonance(NMR) and Raman spectroscopy revealed the existence of sixfold coordinated silicon species and network former units(NFUs) in the BaO-SiO2-P2O5 glasses. The glass transition temperature(Tg), which was measured by differential scanning calorimetry, increased rapidly along with the increase of SiO2 from 0 to 10 mol%, then declined and finally increased again, which showed a "Z" trend along with the increase of SiO2 while the density of the glasses showed the opposite trend. When the addition of SiO2 is 16 mol%, Tg decreased to an extremely low value(807.9 K). Besides, the Vickers indentation hardness(Hv) had been significantly enhanced from 4.66 to 6.63 GPa by adding 16 mol% SiO2. Furthermore, the liquid fragility index(m) of the glasses declined slowly firstly and then increased rapidly when the amount of SiO2 is greater than 13 mol%.展开更多
Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making th...Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making them a highly promising technology for low-grade heat recovery and utilization.However,the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn^(2+)hinder their development.Herein,we present a highperformance thermal charging cell design using Zn^(2+)/NH_(4)^(+)hybrid ion electrolyte,which not only maintains the high output voltage of the Zn-based thermoelectric system,but also significantly enhances the output power density due to the fast diffusion kinetics of NH_(4)^(+).Based on this strategy,the thermal charging cell displays a high thermopower of 12.5 mV K^(-1)and an excellent normalized power density of 19.6 mW m^(-2)K^(-2)at a temperature difference of 35 K.The Carnot-relative efficiency is as high as 12.74%.Moreover,it can operate continuously for over 72 h when the temperature difference persists,achieving a balance between thermoelectric conversion and output.This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.展开更多
基金Funded by National Natural Science Foundation of China(Nos.51772223,51372180)
文摘We studied the local structure and properties of six-fold coordinated silicon(Si[6]) in BaOSiO2-P2O5 glasses. Nuclear magnetic resonance(NMR) and Raman spectroscopy revealed the existence of sixfold coordinated silicon species and network former units(NFUs) in the BaO-SiO2-P2O5 glasses. The glass transition temperature(Tg), which was measured by differential scanning calorimetry, increased rapidly along with the increase of SiO2 from 0 to 10 mol%, then declined and finally increased again, which showed a "Z" trend along with the increase of SiO2 while the density of the glasses showed the opposite trend. When the addition of SiO2 is 16 mol%, Tg decreased to an extremely low value(807.9 K). Besides, the Vickers indentation hardness(Hv) had been significantly enhanced from 4.66 to 6.63 GPa by adding 16 mol% SiO2. Furthermore, the liquid fragility index(m) of the glasses declined slowly firstly and then increased rapidly when the amount of SiO2 is greater than 13 mol%.
基金supported by the Leading Edge Technology of Jiangsu Province(BK20222009-X.Z.,BK20202008-X.Z.)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)National Undergraduate Innovation Training Program of NUAA(202410287179Y).
文摘Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making them a highly promising technology for low-grade heat recovery and utilization.However,the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn^(2+)hinder their development.Herein,we present a highperformance thermal charging cell design using Zn^(2+)/NH_(4)^(+)hybrid ion electrolyte,which not only maintains the high output voltage of the Zn-based thermoelectric system,but also significantly enhances the output power density due to the fast diffusion kinetics of NH_(4)^(+).Based on this strategy,the thermal charging cell displays a high thermopower of 12.5 mV K^(-1)and an excellent normalized power density of 19.6 mW m^(-2)K^(-2)at a temperature difference of 35 K.The Carnot-relative efficiency is as high as 12.74%.Moreover,it can operate continuously for over 72 h when the temperature difference persists,achieving a balance between thermoelectric conversion and output.This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.
