柔性锂离子电池负极材料的制备及性能研究

The portable electronics with light weight and high flexibility have drawn significant attentions recently. Traditional lithium-ion batteries have been unable to meet the requirements of flexible electronic equipment for energy storage devices due to their inflexibility and heavy weight. Obviously, it is imminent to develop high performance lithium-ion batteries with good flexibility, high energy density and excellent rate performance. As an important part of the batteries, the development of flexible electrodes becomes one main research focus. Currently, the electrochemical performance of flexible electrodes still cannot reach the level of traditional ones, which makes them unable to meet the needs of practical use. Due to the highest theoretical specific capacity, silicon-based anodes have drawn great attention. However, silicon anodes suffer from intense volume changes while charging and discharging, and are easy to depart from current collector while bending and folding, both of which result to the failure of electrodes. In this work, we pioneer to put forward the preparation of 3-dimensinal flexible micro-nanostructure array current collector combining the electrospinning technology and the electroless-/electro-deposition process. After covered with thin Si film, we will devolep flexible Si anode based on current collector mentioned above.

轻、薄、柔性化是便携电子产品的重要发展趋势。传统的锂离子电池因其质量重和不可弯折等缺点已经无法满足柔性电子设备对储能器件的要求。研制出更轻更薄且具有优异可弯曲性能，同时具备高能量密度、卓越的倍率性能的锂离子电池迫在眉睫。电极作为锂离子电池的重要组成部分，柔性电极材料的开发成为柔性储能领域的研究热点之一。目前，柔性电极材料研究中遇到的瓶颈问题，主要体现在电池的电化学性能仍未达到传统锂离子电池水平，无法满足实际使用的需要。硅基负极材料由于具有最高的理论比容量而备受关注，然而硅负极在嵌脱锂过程中体积变化剧烈，在弯折过程由于自身脆性很容易与集流体分离，这两种现象都直接导致材料失效。针对上述问题，本论文开创性地提出将静电纺丝技术和化学/电化学沉积工艺两种方法相结合来制备三维柔性微纳米阵列集流体，结合硅薄膜制备技术，拟开发基于三维柔性微纳米阵列集流体的锂电池硅负极。

在全球气候变暖，煤矿、石油等众多不可再生资源匮乏的今天，新能源的发展、能源与环境问题，是全人类共同关注的话题。为了解决这一问题，科研工作者一般从两个方面进行：1、发展可持续、环境友好的新的能源以逐步替代化石能源（锂电池）；2、开发可持续、环境友好、清洁的能源转换方式（电化学氮气还原）。申请人围绕新能源这一主题从锂电池电极材料和电化学氮气还原两个方面开展工作，已发表4篇SCI论文，一篇EI论文，申请专利一项，包括Journal of Power Sources、Carbon、Frontiers in Energy Research、Materials Chemistry and Physics. 在本项目的资助下，申请人紧紧围绕如何设计新一代高比容量、长循环寿命、快冲放电速率的锂离子电池电极材料以及在电催化领域的延伸开展工作：（1）开发出的简单、高效、廉价的微纳米锥阵列结构作为集流体取代传统的二维集流体，结合硅薄膜制备技术，开发基于三维集流体的锂电池硅负极材料，1.5 C下循环1500次，放电容量仍保持在1000 mAhg-1以上；（2）制备了N-C@SnOx纳米复合结构，该复合结构在碱金属离子(Na/Li)电池中展现了优异的性能； （3）通过一步水热法合成了V2O3纳米环结构，该结构具有可控的尺寸，作为锂离子电池负极材料，电化学性能优异，并拓展了其在室温电化学氮气还原领域的应用；（4）锂硫二次电池凭借其高比容量（1675 mAh/g）、高能量密度（2600 Wh/kg）、低成本以及环境友好的优点具有更高的经济利益和发展前景，为了抑制锂硫电池中多硫化物的穿梭效应以及锂枝晶的形成，非晶TiSx被用做隔膜修饰材料，TiSx隔膜修饰层不仅限制了多硫化物，而且促进了电荷传输，从而提高了其电化学性能。