CHEMISTRY OF MATERIALS
·
2015
·
IF 8.354
Xiaoming Zhou,Peng Gao,Shuchao Sun,Di Bao,Ying Wang,Xiaobo Li,Tingting Wu,Yujin Chen,Piaoping Yang
Selenium is applied as the cathode material of lithium/selenium (Li–Se) battery, which has high theoretical volumetric capacity density (3253 mA h·cm–3) and high output voltages. However, it has a low melting point (494 K) and a large sensitivity to thermal treatment, which often result in the phase transition between crystalline Se (trigonal phase) and amorphous Se during the charge/discharge cycles of Li–Se battery as reported in literatures. In order to clarify the different chemical (de)lithiation mechanisms between them in Li–Se battery, in this work large-area amorphous selenium (a-Se) nanowires (NWs) have been successfully prepared first through a facile high-energy ball-milling method. Subsequently the crystalline (c) and crystalline/amorphous (c/a) selenium NWs have also been prepared through annealing the above as-obtained amorphous products, respectively. The affirmative composition and morphology of the as-obtained Se nanostructures have been demonstrated by the XRD, SEM, TEM, HRTEM and Raman spectra measurements. And their specific surface area and pore size distribution have also been analyzed by BET measurements. Finally, it is proved that the as-obtained NWs used as the cathode material of Li–Se battery displayed different chemical reaction processes with Li+ and the related various storage capacities (a-Se: 755 mAh·g–1; c/a-Se: 705 mAh·g–1; c-Se: 250 mAh·g–1). This work has helped us to better understand and correlate the formation of intermediate phases with the electrochemical performance of Li–Se cells and shines new light on how to improve the cell performance by turning the phase of Se.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ChemistryOpen
·
2022
·Vol. 11
·期 3
·e202100296
·
IF 2.63
Han Hu,Fangchao Liu,Zhongli Shen,Rui Yan,Zhengwen Fu
Graphical An amorphous selenium graphene composite (a-Se/rGO) and a crystalline selenium nanorods graphene composite (b-Se/rGO) were prepared. Different electrochemical properties of amorphous selenium and selenium nanorods were analyzed. Amorphous selenium shows a good utilization rate in the first discharge, but the utilization rate decreases with the growth of crystals. Selenium (Se) is an element in the same main group as sulfur and is characterized by high electrical conductivity and large capacity (675 mAh g −1 ). Herein, a novel ultra-high dispersion amorphous selenium graphene composite (a-Se/rGO) was synthesized and a selenium nanorods graphene composite (b-Se/rGO) was prepared by hydrothermal method as the cathode material for all solid-state lithium−selenium (Li−Se) batteries, hoping to improve the efficiency and utilization rate of active substances in all solid-state batteries. The all-solid-state batteries were assembled using a heated thawing electrolyte (2LiIHPN−LiI; HPN=3-hydroxypropionitrile). The utilization rate of a-Se/rGO was 103 % and the capacity was 697 mAh g −1 , which remained at 281 mAh g −1 (41.6 % of the 675 mAh g −1 ) after 30 cycles under 0.5 C. Notably, a-Se/rGO showed excellent performance concerning its utilization rate, with a capacity of up to 610 mAh g −1 at 2 C, due to the high availability of amorphous Se and the special properties of the electrolytes. However, in the charge and discharge cycles, the second discharge capacity of a-Se/rGO was more significantly attenuated than that of the first discharge due to the formation of larger crystals of selenium during the charging process. The battery assembled using b-Se/rGO maintained a capacity of 270.58 mAh g −1 after 30 cycles (the retention rate of discharge capacity was 66.13 % compared with that in the first cycle). Through TEM and other relevant tests, it is speculated that amorphous selenium is conducive to capacity release, which, however, is affected by the formation of crystalline selenium after the first charge process.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Science
·
2019
·Vol. 6
·期 19
·1900531
·
IF 15.804
Chenyang Xing,Dazhou Huang,Shiyou Chen,Qichen Huang,Chuanhong Zhou,Zhengchun Peng,Jiagen Li,Xi Zhu,Yizhen Liu,Zhipeng Liu,Houkai Chen,Jinlai Zhao,Jiangqing Li,Liping Liu,Faliang Cheng,Dianyuan Fan,Han Zhang
Herein, a core–shell tellurium–selenium (Te–Se) nanomaterial with polymer-tailed and lateral heterojunction structures is developed as a photothermal absorber in a bionic solar-evaporation system. It is further revealed that the amorphous Se shell surrounds the crystalline Te core, which not only protects the Te phase from oxidation but also serves as a natural barrier to life entities. The core (Te)–shell (Se) configuration thus exhibits robust stability enhanced by 0.05 eV per Se atom and excellent biocompatibility. Furthermore, high energy efficiencies of 90.71 ± 0.37% and 86.14 ± 1.02% and evaporation rates of 12.88 ± 0.052 and 1.323 ± 0.015 kg m −2 h −1 are obtained under 10 and 1 sun for simulated seawater, respectively. Importantly, no salting out is observed in salt solutions, and the collected water under natural light irradiation possesses extremely low ion concentrations of Na + , K + , Ca 2+ , and Mg 2+ relative to real seawater. Considering the tunable electronic structures, biocompatibilities, and modifiable broadband absorption of the solar spectrum of lateral heterojunction nanomaterials of Te–Se, the way is paved to engineering 2D semiconductor materials with supporting 3D porous hydrophilic materials for application in solar desalination, wastewater treatment, and biomedical ventures.
研究领域:
材料科学
·
纳米技术
·
太阳能
·
环境工程
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）