ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Yaoming Deng,Tianxing Kang,Zhen Ma,Xinxin Tan,Xiaona Song,Zheng Wang,Peipei Pang,Dong Shu,Xiaoxi Zuo,Junmin Nan
Under the abusive conditions, it is demonstrated that the thermal stability of LiCoO 2 and the safety of LiCoO 2 /graphite batteries are improved by doping and coating Al and Ti elements into the bulk structure and surface of LiCoO 2 . The trickle charge and the differential scanning calorimeter (DSC) results show that after coating Al and Ti oxides on the doped LiCoO 2 with 2000 ppm Al, the exothermic peak shifts to a higher temperature and the exotherm decreases, resulting in the increase of the thermal stability of LiCoO 2 . In addition, compared to the LiCoO 2 without Al doping, it is also indicated that the thermal stability of LiCoO 2 can be enhanced by doping Al, the exothermic peak of the LiCoO 2 with Al doping amount of 10000 ppm is up to 250 °C. Under the abusive testing conditions including thermal shock and overcharge, the safety evaluation results of pouch polymer LiCoO 2 /graphite batteries are in good agreement with the trickle charge and DSC results. These results reveal that the thermal stability of LiCoO 2 can be used as an indicator to evaluate the safety characteristics of LiCoO 2 /graphite batteries, and especially the introduction of Al and Ti into LiCoO 2 can effectively improve the safety of LiCoO 2 /graphite batteries under the abusive conditions.
研究领域:
材料科学
·
电池安全
✓ 已验证
产品关联
DOI
高影响因子
Applied Materials Today
·
2022
·
IF 8.663
Xuefeng Zhang,Xudong Liu,Yufang Feng,Si Qiu,Youxiang Shao,Qingyu Liao,Hao Li,Yong Liu
In this paper, a simple and scalable process combining hydrothermal and etching was designed to prepare an in situ surface-modified mesoporous MXene, Ti 3 C 2 T x , based on the synergistic effect of surface modification and mesoporous structure. It resulted that, the ion diffusion resistance was effectively reduced owing to the shortened ion diffusion pathway, and the pseudo-capacitance was significantly enhanced due to the increase of surface redox active sites by the modification of oxygen-containing groups. Meanwhile, the advantage of compact energy storage for Ti 3 C 2 T x was retained. At the current density of 2 A g − 1 , the volumetric capacitance reached 2079 F cm −3 (loading at 2.6 mg cm −2 ). As the current density increasing to 36 A g − 1 , 83% (1732 F cm −3 ) of its initial volumetric capacitance was maintained showing excellent rate performance. In addition, the replacement of the fluorine group by the oxygen-containing group during the in-situ modification reduced the reduction state of the titanium element in Ti 3 C 2 T x , achieving improved environmental stability. This work proposes a new strategy for MXenes to expand their potential application in the field of compact energy storage. At the same time, the suggested strategy based on "endogenous" modification is expected to provide new ideas to improve antioxidation ability of MXenes.
研究领域:
材料科学
·
储能技术
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
·
IF 14.3
Yao Li,Yongheng Jin,Hassan Raza,Yuping Wang,Qingkui Chen,Xingjian Zou,Zhengyang Ren,Junjie Guo,Guangping Zheng,Junye Cheng
Recently, the strategy of tuning the dielectric parameters of absorbers for their excellent electromagnetic wave absorption (EMA) performance has attracted much attention. Among those candidates used for EMA application, high-entropy oxides (HEOs) can be implemented with this strategy due to their rich composition modulability. In this work, a series of implementation approaches varying from elemental design to structural modulation are employed to modulate the dielectric parameters of HEOs, resulting in their excellent EMA performance. The addition of Ti element optimizes the dipole distribution at the microscopic scales, improving the dielectric polarization of the materials. Moreover, a composite material is constructed by physically blending HEO with acetylene black (ACET), which significantly improves the macroscopic conduction loss of the material. The optimization of the dielectric genes of HEO/ACET is achieved with the blending effect and excellent EMA performance could be obtained. Among them, HEO with 17.5% ACET addition exhibits dual-band absorption, while Ti-HEO containing Ti element exhibits not only low-frequency absorption with reflection loss (RL) up to −29.81 dB at C-band but broadband absorption over 6 GHz as well as an optimal RL value up to −52.31 dB. In addition to the development of innovative EMA materials, this study offers a new perspective on how the EMA characteristics can be effectively regulated.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2024
·Vol. 14
·期 10
·910
·
IF 2.4
Meihong Huang,Junhui Lin,Zhiyong Liang,Shaowei Chen,Yuling Zhong,Feng Wang,Bixian Chen,Dongxia Zhang
The addition of flexible Cu2ZnSnS4 (CZTS) thin film solar cells to titanium (Ti) substrates is an attractive way to achieve the low-cost manufacturing of photovoltaics. Prior research has indicated that the appropriate diffusion of Ti elements can enhance the crystalline growth of CZTS films. However, the excessive diffusion of Ti has been shown to adversely affect the photovoltaic performance of CZTS photovoltaic devices. Therefore, it is essential to regulate the diffusion of Ti elements within CZTS thin films to optimize their photovoltaic properties. The tendency for Ti substrate elements to diffuse into CZTS films is also influenced by the activation energy associated with these Ti elements. The sulfurization temperature is posited to be a critical factor in modulating the diffusion and activation energy of Ti elements within CZTS thin films. Consequently, this research investigates the alteration of the sulfurization temperature of CZTS thin films in order to enhance the properties of these thin films and to examine the diffusion behavior of titanium elements. The results reveal that as the sulfurization temperature increases, the diffusion of Ti elements within the CZTS thin films initially increases, then decreases, and subsequently increases again. This pattern suggests that the diffusion of Ti elements is affected not only by the activation energy of the Ti elements but also by the defect hopping distance within the CZTS thin films. Notably, at a sulfurization temperature of 550 °C, the grains at the base of the CZTS thin film demonstrate an increased density, which is associated with a reduced defect hopping distance, thereby hindering the diffusion of Ti elements within the CZTS thin films. Furthermore, at this specific sulfurization temperature, the slope of the current–voltage (I–V) curve for the CZTS/Ti structure reaches its maximum, indicating optimal ohmic contact characteristics.
研究领域:
材料科学
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2024
·
IF 6.2
Chenlong Wei,Xuexiang Wang,Peng Tong,Peng Wang,Jun Wen
Due to the low bonding strength between diamond and copper, the thermal conductivity and mechanical strength of diamond/copper composites are affected. In order to improve the interface bonding strength, this paper prepared diamond/Cu composites with titanium element in two forms: adding titanium to the copper matrix and using titanium coated diamond particles, respectively. The microstructure and composition analysis of the materials were carried out through SEM, EDS, AFM, etc. The bending strength and thermal conductivity of titanium coated diamond/copper composites reached 230 MPa and 480 W/(m·K), respectively, which were higher than the bending strength and thermal conductivity of diamond/Cu composites with added titanium in the matrix (208 MPa and 127 W/(m·K) and significantly higher than the corresponding properties of pure diamond/Cu composites (69 MPa and 108 W/(m·K)). Pre coating a layer of titanium carbide on the surface of diamond can serve as a connecting bridge, effectively reducing interfacial thermal resistance and improving mechanical properties, which is more effective than adding titanium powder to the matrix to improve the bending strength and thermal conductivity of diamond/Cu composites.
研究领域:
材料科学
·
复合材料工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）