JOURNAL OF ELECTRONIC MATERIALS
·
2017
·Vol. 47
·期 6
·3248-3253
·
IF 1.579
Chen Jun-Liang,Liu Chengyan,Miao Lei,Gao Jie,Zheng Yan-yan,Wang Xiaoyang,Lu Jiacai,Shu Mingzheng
With excellent high-temperature stability (up to 1000 K) and favorable electrical properties for thermoelectric application, TiNiSn-based half-Heusler (HH) alloys are expected to be promising thermoelectric materials for the recovery of waste heat in the temperature ranging from 700 K to 900 K. However, their thermal conductivity is always relatively high (5–10 W/mK), making it difficult to further enhance their thermoelectric figure-of-merit ( ZT ). In the past decade, introducing nano-scale secondary phases into the HH alloy matrix has been proven to be feasible for optimizing the thermoelectric performance of TiNiSn. In this study, a series of TiNiSn-based alloys have been successfully synthesized by a simple solid-state reaction. The content and composition of the heterogeneous phase (TiNi 2 Sn and Sn) is accurately regulated and, as a result, the thermal conductivity successfully reduced from 4.9 W m −1 K −1 to 3.0 Wm −1 K −1 (750 K) due to multi-scale phonon scattering. Consequently, a ZT value of 0.49 is achieved at 750 K in our TiNiSn-based thermoelectric materials. Furthermore, the thermal stability of TiNiSn alloys is enhanced through reducing the Sn substance phase.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2023
·
IF 9.2
Jiaming Yang,Jun Zhou,Zhengrong Liu,Yueyue Sun,Chaofan Yin,Kaiteng Wang,Ruhuan Li,Zilin Zhou,Kai Wu
In-situ exsolution technique, as an efficient and controllable strategy of surface modification, has been extensively applied in reversible solid oxide cells (RSOCs). Here, we demonstrate La x Sr x Ti 0.9 Ni 0.1 O 3-δ fiber decorated by exsolved Ni nanoparticles and highlight the impacts of A-site deficiency on Ni exsolution and electrochemical performance of RSOCs. The La 0.4 Sr 0.4 Ti 0.9 Ni 0.1 O 3 (A/B = 0.8) fibrous fuel electrode decorated by Ni nanoparticles with moderate Ni exsolution displays optimum electrochemical performance at 800 °C, achieving ∼540 mW cm −2 in SOFC mode and −0.742/0.385 A cm −2 under 1.3/0.7 V in RSOC mode. In contrast, high A-site deficiency (A/B < 0.8) allows heterogeneous phases (NiTiO 3 ) and excessive Ni exsolution along with alterations of fibrous morphology, leading to slow gas diffusion, sluggish catalysis, and Ni agglomeration. The distribution of relaxation time (DRT) results show that the rate-limiting steps in symmetrical cells are gas diffusion, hydrogen adsorption, and dissociation, accounting for over 89% of the total R P . Ni-equilibrium model based on X-ray Rietveld refinement calculates the degree of exsolution with various A-site deficiency, revealing NiTiO 3 is the key factor of excessive exsolution. Our work of high A-site deficiency exemplified here may serve in the design and nanoengineering of fibrous ABO 3 perovskite oxides for RSOCs.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Energy Materials
·
2019
·Vol. 9
·期 31
·1901634
·
IF 24.884
Hailong Xiong,Lanlan Wu,Yu Liu,Tunan Gao,Kaiqian Li,Yan Long,Rui Zhang,Ling Zhang,Zhen-An Qiao,Qisheng Huo,Xin Ge,Shuyan Song,Hongjie Zhang
Multiphasic titanium dioxide (TiO 2 ) possessing abundant heterophase junctions have been widely used for various photocatalytic applications. Current synthesis of multiphasic TiO 2 mainly involves the process of thermal treatment and multiple steps of rigorous reactions, which is adverse to controlling the crystal phases and phase ratios of multiphasic TiO 2 . Meanwhile, the resulting products have relatively low surface area and nonporous structure. Here, a facile polymer-assisted coordination-mediated self-assembly method to synthesize mesoporous TiO 2 polymorphs with controllable heterophase junctions and large surface area by using polyethylenimine as the porogen in an acidic aqueous synthesis system is reported. Using this approach, the crystal phases (triphase, biphase, and monophase) and phase compositions (0–100%) are easily tailored by selecting the suitable acidic media. Furthermore, the specific surface areas (77–228 m 2 g −1 ) and pore sizes (2.9–10.1 nm) are readily tailored by changing the reaction temperature. The photocatalytic activity of mesoporous TiO 2 polymorphs is evaluated by photocatalytic hydrogen evolution. The triphasic TiO 2 exhibits an excellent photocatalytic H 2 generation rate of 3.57 mmol h −1 g −1 as compared to other polymorphs, which is attributed to the synergistic effects of heterophase junctions and mesostructure. The band diagram of possible electron transfer pathway for triphasic TiO 2 is also elucidated.
研究领域:
材料化学
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光催化
·
纳米材料
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能源科学
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表面科学
·
无机合成
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Baotong Cao,Jinhua Shi,Qingfeng Liu,Fanbin Hu,Haigang Dong,Zitong Fei,Qi Meng,Peng Dong
The recycling of spent lithium-ion batteries is a critical link in the global transition to new energy systems. Direct single-crystal regeneration has emerged as a key research direction for recycling of spent cathode materials, yet it faces inherent conflicts between high-temperature kinetics for single-crystal transformation and structural stability, and the dilemma of balancing particle fragmentation with crystal integrity. Herein, the study presents a strategy of targeted etching of heterogeneous phases and crystal-induced regrowth to achieve efficient single-crystal regeneration of spent cathode materials. In the molten salt-mediated system, the precise etching of the rock-salt phase via Cl − penetration induces local lattice distortion and stress accumulation, leading to the controlled and oriented cleavage of polycrystalline particles. Leveraging the strong ion migration effect, this process facilitates simultaneous relithiation and single-crystal regeneration. Owing to the restored morphological and structural integrity, the regenerated single-crystal cathode delivers a high initial discharge capacity of 183.60 mAh g −1 at 1C and an exceptional capacity retention of 93% after 100 cycles. Economic and environmental analysis further confirms the significant cost advantage of this strategy over conventional pyrometallurgical and hydrometallurgical recycling routes. This study provides an innovative solution for the direct regeneration of cathode materials in spent lithium-ion batteries.
研究领域:
材料科学
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储能技术
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回收技术
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电化学
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可持续工程
✓ 已验证
产品关联
DOI
高影响因子
Chem Catalysis
·
2023
·
IF 9.4
Rong Wang,Yue Peng,Jane Chung,Zhen Chen,Xiyang Wang,Haibo Yin,Yimin A. Wu,Jingshan Luo,Junhua Li
Summary The electrocatalytic reduction of CO 2 is an attractive method for reducing greenhouse gases and producing chemical feedstocks. However, the activation of C=O bonds limits the reaction kinetics; therefore, understanding the mechanism of C=O bond activation can guide the design of high-performance catalysts. Here, we investigate the C=O bond activation mechanism during the electroreduction of CO 2 to CO on ZnO. Using in situ experimental techniques and quantum chemical calculations , we find that defects in ZnO promote the formation of Zn–ZnO x interfaces during CO 2 reduction, which mediates an intimate-junction exciton state by the metal semiconductor heterophase. This promotes the formation of CO 2 radicals, exposing electron donation centers for CO 2 adsorption and redox centers for cleaving stable C=O bonds. The internal electric field generated by the heterojunction enhances the initial C=O activation by facilitating the interaction between the metalized Zn d-orbital and the O π -orbital in CO 2 .
研究领域:
电化学
·
材料科学
·
催化
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
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