Haridas Anupriya K, Heo Jungwon, Liu Ying, Ahn Hyo-Jun, Zhao Xiaohui, Deng Zhao, Agostini Marco, Matic Aleksandar, Cho Kwon-Koo, Ahn Jou-Hyeon
Soochow Institute for Energy and Materials Innovations, College of Physics, Optoelectronics and Energy, Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies , Soochow University , 1 Shizi Street , Suzhou 215006 , PR China.
Department of Physics , Chalmers University of Technology , 41296 Göteborg , Sweden.
ACS Appl Mater Interfaces. 2019 Aug 21;11(33):29924-29933. doi: 10.1021/acsami.9b09026. Epub 2019 Aug 8.
In order to satisfy the escalating energy demands, it is inevitable to improve the energy density of current Li-ion batteries. As the development of high-capacity cathode materials is of paramount significance compared to anode materials, here we have designed for the first time a unique synergistic hybrid cathode material with enhanced specific capacity, incorporating cost-effective iron sulfide (FeS) nanoparticles in a sulfurized polyacrylonitrile (SPAN) nanofiber matrix through a rational in situ synthesis strategy. Previous reports on FeS cathodes are scarce and consist of an amorphous carbon matrix to accommodate the volume changes encountered during the cycling process. However, this inactive buffering matrix eventually increases the weight of the cell, reducing the overall energy density. By the rational design of this hybrid composite cathode, we ensure that the presence of covalently bonded sulfur in SPAN guarantees high sulfur utilization, while effectively buffering the volume changes in FeS. Meanwhile, FeS can compensate for the conductivity issues in the SPAN, thereby realizing a synergistically driven dual-active cathode material improving the overall energy density of the composite. Simultaneous in situ generation of FeS nanoparticles within the SPAN fiber matrix was carried out via electrospinning followed by a one-step heating procedure. The developed hybrid cathode material displays enhanced lithium-ion storage, retaining 688.6 mA h g at the end of 500 cycles at 1 A g even within a narrow voltage range of 1-3.0 V. A high discharge energy density > 900 W h kg, much higher than the theoretical energy density of the commercial LiCoO cathode, was also achieved, revealing the promising prospects of this hybrid cathode material for high energy density applications.
为了满足不断增长的能源需求，提高当前锂离子电池的能量密度是不可避免的。由于与负极材料相比，高容量正极材料的开发具有至关重要的意义，在此我们首次设计了一种独特的具有增强比容量的协同混合正极材料，通过合理的原位合成策略将具有成本效益的硫化铁（FeS）纳米颗粒掺入硫化聚丙烯腈（SPAN）纳米纤维基质中。先前关于FeS正极的报道很少，且由无定形碳基质组成以适应循环过程中遇到的体积变化。然而，这种无活性的缓冲基质最终增加了电池的重量，降低了整体能量密度。通过对这种混合复合正极的合理设计，我们确保SPAN中共价键合硫的存在保证了高硫利用率，同时有效地缓冲了FeS中的体积变化。与此同时，FeS可以弥补SPAN中的导电性问题，从而实现协同驱动的双活性正极材料，提高复合材料的整体能量密度。通过静电纺丝然后进行一步加热程序，在SPAN纤维基质中同时原位生成FeS纳米颗粒。所开发的混合正极材料显示出增强的锂离子存储能力，即使在1 - 3.0V的窄电压范围内，在1A g的电流密度下500次循环结束时仍保持688.6 mA h g。还实现了高于商业LiCoO正极理论能量密度的> 900 W h kg的高放电能量密度，揭示了这种混合正极材料在高能量密度应用中的广阔前景。
