通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构,对这种核壳结构的正极材料进行了结构和形貌表征,并研究了其电化学性能.研究发现,尖晶石相为材料提供了三维锂离子迁移通道,碳包覆层显著提高了正极材料...通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构,对这种核壳结构的正极材料进行了结构和形貌表征,并研究了其电化学性能.研究发现,尖晶石相为材料提供了三维锂离子迁移通道,碳包覆层显著提高了正极材料的电子电导率,两种效应的共同作用极大降低了材料的电化学阻抗,提升了材料的放电比容量,这种多壳层结构正极材料还具有优异的倍率性能,在5C倍率下放电比容量可达到135.1 m A·h/g.展开更多
The development of China’s space industry puts forward urgent requirements for high-performance debris shielding materials and high energy density rechargeable battery.In this review,the recent progress on debris shi...The development of China’s space industry puts forward urgent requirements for high-performance debris shielding materials and high energy density rechargeable battery.In this review,the recent progress on debris shielding fibrous materials and high energy density Li-S battery are particularly summarized.According to the experimental results,basalt fibers and silicon carbide fibers were chosen as the effective filling shielding materials.The geometric structure of fabrics was also investigated.For the novel shielding materials,high-strength and flexible silicon carbide micro-nano fibrous membranes were designed and fabricated.The obtained membranes with excellent mechanical properties portend the potential applications in debris protection structure.Furthermore,the high specific energy lithium sulfur batteries have made remarkable progress in fundamental research and application research in recent years.In order to solve the key problems of polysulfides shuttle and slow redox kinetics in lithium sulfur battery,a series of transition metal compound@hollow carbon-based material as sulfur host with dual functions of catalysis and adsorption towards polysulfides were designed and constructed.The obtained Li-S pouch cells with high areal sulfur loading of 6.9 mg·cm^(-2)yield exceptional high practical energy density of 382 W·h·kg^(-1)under lean electrolyte of 3.5μL·mg^(-1),demonstrating the great potential of realistic high-energy Li-S batteries.展开更多
Using polymer-derived technology, continuous high-temperature resistant Si-Al-C fibers were prepared by one step method, which included melt-spinning of polya-luminocarbosilane (PACS), curing of continuous PACS fibers...Using polymer-derived technology, continuous high-temperature resistant Si-Al-C fibers were prepared by one step method, which included melt-spinning of polya-luminocarbosilane (PACS), curing of continuous PACS fibers, and sintering of the cured products. The results show that the average diameter and tensile strength of continuous Si-Al-C fibers are 11 to 12 μm and 1.8 to 2.0 GPa, respectively. The chemical formula of Si-Al-C fibers is SiC1.01O0.0400Al0.024, which is nearly stoichometric. The fibers are mainly composed of β-SiC crystalline, small amount of α-SiC, and amorphous SiC. Continuous Si-Al-C fibers exhibit excellent thermal stability. When the fibers were exposed in argon for 1 h, the tensile strength did not decrease until 1500℃. After heat treatment at 1800℃ in argon for 1 h, the fibers maintained about 80% of the initial strength. It was higher than that of Nicalon and Hi-Nicalon fibers.展开更多
文摘通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构,对这种核壳结构的正极材料进行了结构和形貌表征,并研究了其电化学性能.研究发现,尖晶石相为材料提供了三维锂离子迁移通道,碳包覆层显著提高了正极材料的电子电导率,两种效应的共同作用极大降低了材料的电化学阻抗,提升了材料的放电比容量,这种多壳层结构正极材料还具有优异的倍率性能,在5C倍率下放电比容量可达到135.1 m A·h/g.
基金Supported by the National Natural Science Foundation of China(52002400)Young Elite Scientists Sponsorship Program by CAST(YESS20200093)。
文摘The development of China’s space industry puts forward urgent requirements for high-performance debris shielding materials and high energy density rechargeable battery.In this review,the recent progress on debris shielding fibrous materials and high energy density Li-S battery are particularly summarized.According to the experimental results,basalt fibers and silicon carbide fibers were chosen as the effective filling shielding materials.The geometric structure of fabrics was also investigated.For the novel shielding materials,high-strength and flexible silicon carbide micro-nano fibrous membranes were designed and fabricated.The obtained membranes with excellent mechanical properties portend the potential applications in debris protection structure.Furthermore,the high specific energy lithium sulfur batteries have made remarkable progress in fundamental research and application research in recent years.In order to solve the key problems of polysulfides shuttle and slow redox kinetics in lithium sulfur battery,a series of transition metal compound@hollow carbon-based material as sulfur host with dual functions of catalysis and adsorption towards polysulfides were designed and constructed.The obtained Li-S pouch cells with high areal sulfur loading of 6.9 mg·cm^(-2)yield exceptional high practical energy density of 382 W·h·kg^(-1)under lean electrolyte of 3.5μL·mg^(-1),demonstrating the great potential of realistic high-energy Li-S batteries.
基金the National Natural Science Foundation of China (Grant No. 59972042)
文摘Using polymer-derived technology, continuous high-temperature resistant Si-Al-C fibers were prepared by one step method, which included melt-spinning of polya-luminocarbosilane (PACS), curing of continuous PACS fibers, and sintering of the cured products. The results show that the average diameter and tensile strength of continuous Si-Al-C fibers are 11 to 12 μm and 1.8 to 2.0 GPa, respectively. The chemical formula of Si-Al-C fibers is SiC1.01O0.0400Al0.024, which is nearly stoichometric. The fibers are mainly composed of β-SiC crystalline, small amount of α-SiC, and amorphous SiC. Continuous Si-Al-C fibers exhibit excellent thermal stability. When the fibers were exposed in argon for 1 h, the tensile strength did not decrease until 1500℃. After heat treatment at 1800℃ in argon for 1 h, the fibers maintained about 80% of the initial strength. It was higher than that of Nicalon and Hi-Nicalon fibers.
