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Thermoelectric Peltier coolers (PCs) are being increasingly used as temperature stabilizers for optoelectronic devices. Increasing integration drives PC miniaturization, requiring thermoelectric materials with good strength. We demonstrate a simultaneous gain of thermoelectric and mechanical performance in (Bi, Sb)2Te3, and successfully fabricate micro PCs (2 × 2 mm2 cross-section) that show excellent maximum cooling temperature difference of 89.3 K with a hot-side temperature of 348 K. A multi-step process involving annealing, hot-forging and composition design, is developed to modify the atomic defects and nano- and microstructures. The peak ZT is improved to ∼1.50 at 348 K, and the flexural and compressive strengths are significantly enhanced to ∼140 MPa and ∼224 MPa, respectively. These achievements hold great potential for advancing solid-state refrigeration technology in small spaces. [ABSTRACT FROM AUTHOR]

Degenerate semiconductors usually demonstrate a metallic‐like conduction behavior, showing limited carrier mobility at high temperatures. Herein, by incorporating B4C nanoparticles into the Cu1.99Se system, an unusual switch from the "degenerate" to "non‐degenerate" semiconducting behavior is revealed as a result of the engineered interfaces. Heterogeneous interfaces and disordered Cu2Se amorphous phases are introduced in the Cu1.99Se/B4C composites, which generate a trapping effect against the mobile Cu ions, leading to a distinctive "hump" signature for electrical conductivity. Benefiting from this rare high‐temperature thermoelectric response, a high power factor is obtained due to reduced carrier concentration and enhanced mobility, and low lattice thermal conductivity is retained because of relatively stronger anharmonic lattice vibrations. Consequently, the Cu1.99Se + 0.9 vol.% B4C sample at least achieves a maximum thermoelectric figure of merit (ZT) of 2.6 at 1025 K with synergistically enhanced mechanical robustness. The present interface engineering strategy may be applicable to other thermoelectric materials with ionic migration characteristics. [ABSTRACT FROM AUTHOR]

As an energy harvesting device, the newly emerged thermocell has attracted great interest. However, it requires an additional energy storage device to complete a functional recycling system. As the core part of energy harvesting and storage devices, the design of electrodes with both high thermoelectric and electrochemical conversion efficiencies is particularly important. Herein, a high‐performance thermocell and supercapacitor device are constructed by employing the same mix‐phase MoSe2‐NiSe/NF electrode for both energy harvesting and storage. The thermocell exhibits an enhanced Seebeck coefficient of −1.69 mV K−1 and a superior output of 0.58 mW m−2 K−2 for low‐grade heat harvesting. Meanwhile, the supercapacitor device shows a great energy density of 54 Wh kg−1 at a power density of 806 W kg−1 and excellent cycling stability with a 92.8% retention rate after 50 000 cycles. This work offers a universal approach for the rational design of synergistic electrode materials to simultaneously achieve high‐energy harvesting and storage devices and lays a foundation for the recycling system of thermoelectric harvesting, conversion, and storage. [ABSTRACT FROM AUTHOR]

This paper reports enhanced high-temperature piezoelectric properties of Bi(Zn0.5Ti0.5)O3-modified BiFeO3-BaTiO3 (BF–BT-xBZT) ceramics prepared by two-step sintering method. The resultant ceramics show a symmetrical transition from a rhombohedral–pseudo-cubic (R-PC) phase coexistence to main PC phase with the increase of x, whose R-PC fraction (CR/CPC) is 53.3/46.7, 52.9/47.1, 50.2/49.8, 27.4/72.6, 15.3/84.7 when x = 0, 0.005, 0.01, 0.03, 0.05, respectively. The modification of BZT inhibits the grain growth, reduces the leakage current and gradually drives ferroelectric to relaxor transition. Optimal piezoelectric properties: d33 = 193 pC N−1, Pr = 20.6 μC cm−2, TC = 503 °C and kp = 36% achieved at x = 0.01 composition, which is due to the synergistic effect of an appropriate CR/CPC ratio, improved insulation and good polarization performance. In addition, the depolarization temperature Td is close 280–312 °C, and the high-temperature d33 further increases to 286–347 pC N−1, which shows a good application prospect of lead-free piezoceramics at high temperature. Our work also confirms that the addition of (Zn0.5Ti0.5)3+ and two-step sintering method are an effective and convenient strategy to improve the high-temperature electrical performance of BiFeO3–BaTiO3 based lead-free ceramics. [ABSTRACT FROM AUTHOR]

GeTe and (Bi,Sb)2Te3 are two representative thermoelectric (TE) materials showing maximum performance at middle and low temperature, respectively. In order to achieve higher performance over the whole temperature range, their segmented one‐leg TE modules are designed and fabricated by one‐step spark plasma sintering (SPS). To search for contact and connect layers, the diffusion behavior of Fe, Ni, Cu, and Ti metal layers in GeTe is studied systematically. The results show that Ti with a similar linear expansivity (10.80 × 10−6 K−1) to GeTe, has low contact resistance (3 µΩ cm2) and thin diffusion layer (0.4 µm), and thus is an effective metallization layer for GeTe. The geometric structure of the GeTe/(Bi,Sb)2Te3 segmented one‐leg TE module and the ratio of GeTe to (Bi,Sb)2Te3 are determined by finite element simulation method. When the GeTe height ratio is 0.66, its theoretical maximum conversion efficiency (ηmax) can reach 15.9% without considering the thermal radiation and thermal/electrical contact resistance. The fabricated GeTe/(Bi,Sb)2Te3 segmented one‐leg TE module showed a ηmax up to 9.5% with a power density ≈ 7.45 mW mm−2, which are relatively high but lower than theoretical predictions, indicating that developing segmented TE modules is an effective approach to enhance TE conversion efficiency. [ABSTRACT FROM AUTHOR]