Carbon Energy
·
2024
·Vol. 6
·期 9
·e565
·
IF 19.5
Mengting Liu,Zhiwei Cheng,Xu Zhu,Haojie Dong,Tianran Yan,Liang Zhang,Lu Zheng,Hu-Rong Yao,Xian-Zuo Wang,Lianzheng Yu,Bing Xiao,Yao Xiao,Peng-Fei Wang
Layered composite oxide materials with O3/P2 biphasic crystallographic structure typically demonstrate a combination of high capacities of the O3 phase and high operation voltages of the P2 phase. However, their practical applications are seriously obstructed by difficulties in thermodynamic phase regulation, complicated electrochemical phase transition, and unsatisfactory cycling life. Herein, we propose an efficient structural evolution strategy from biphase to monophase of Na 0.766+ x Li x Ni 0.33− x Mn 0.5 Fe 0.1 Ti 0.07 O 2 through Li + substitution. The role of Li + substitution not only simplifies the unfavorable phase transition by altering the local coordination of transition metal (TM) cations but also stabilizes the cathode–electrolyte interphase to prevent the degradation of TM cations during battery cycling. As a result, the thermodynamically robust O3-Na 0.826 Li 0.06 Ni 0.27 Mn 0.5 Fe 0.1 Ti 0.07 O 2 cathode delivers a high capacity of 139.4 mAh g −1 at 0.1 C and shows prolonged cycling life at high rates, with capacity retention of 81.6% at 5 C over 500 cycles. This work establishes a solid relationship between the thermodynamic structure evolution and electrochemistry of layered cathode materials, contributing to the development of long-life sodium-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2016
·Vol. 99
·期 11
·3784-3791
·
IF 2.787
Jingkun Yuan,Peigang He,Chao Yang,Dechang Jia,Jinsong You,Shu Yan,Delong Cai,Zhihua Yang,Xiaoming Duan,Shengjin Wang,Jiahuan Xu,Yu Zhou
The purpose of this work was to study the role of lithium in cesium-based geopolymers and the thermal evolution during heat treatment together with thermal expansion behavior of the resulting geopolymer ceramic. A series of lithium-substituted cesium-based geopolymers, Cs (1− x ) Li x GP (where x = 0, 0.1, 0.2, and 0.3), were prepared. All the geopolymer samples were heated at 1300°C for 2 h and thermal evolution on heating was studied by a variety of techniques. Phase composition, microstructure evolution, and thermal expansion behaviors of the ceramics derived from the geopolymers were characterized. All the geopolymer specimens exhibited similar thermal evolutionary trends. With increases in lithium content, overall mass loss increased gradually due to the higher hydration energy of Li + than Cs + . Thermal shrinkage of these specimens can be divided into four stages, i.e., structural resilience, dehydration, dehydroxylation, and sintering, according to the dilatometer results. The introduction of Li results in two-step sintering behavior for the lithium-substituted cesium-based geopolymers. The average thermal expansion coefficient (CTE) of Cs (1− x ) Li x GP ceramics decreased from 4.80 × 10 −6 K −1 ( x = 0) to 3.61 × 10 −6 K −1 ( x = 0.3) with increase in lithium substitution. The reason can be attributed to the presence of spodumene after thermal treatment, which has a relatively low thermal expansion coefficient compared with pollucite. Meanwhile, molten spodumene could serve as a buffer phase between pollucite crystals also conducive to the decline of CTE of this system.
研究领域:
材料科学
·
无机非金属材料
·
陶瓷学
·
热物理性能
·
固废资源化
✓ 已验证
DOI
高影响因子
Science Advances
·
2019
·Vol. 5
·期 1
·
IF 12.804
Ming Zhao,Zhiguo Xia,Xiaoxiao Huang,Lixin Ning,Romain Gautier,Maxim S. Molokeev,Yayun Zhou,Yu-Chun Chuang,Qinyuan Zhang,Quanlin Liu,Kenneth R. Poeppelmeier
Solid-state phosphor-converted white light-emitting diodes (pc-WLEDs) are currently revolutionizing the lighting industry. To advance the technology, phosphors with high efficiency, tunable photoluminescence, and high thermal stability are required. Here, we demonstrate that a simple lithium incorporation in NaAlSiO4:Eu system enables the simultaneous fulfillment of the three criteria. The Li substitution at Al sites beside Na sites in NaAlSiO4:Eu leads to an enhanced emission intensity/efficiency owing to an effective Eu3+ to Eu2+ reduction, an emission color tuning from yellow to green by tuning the occupation of different Eu sites, and an improvement of luminescence thermal stability as a result of the interplay with Li-related defects. A pc-WLED using the Li-codoped NaAlSiO4:Eu as a green component exhibits improved performance. The phosphors with multiple activator sites can facilitate the positive synergistic effect on luminescence properties.
研究领域:
材料科学
·
光电子学
·
固态照明
·
无机化学
·
发光学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）