金属/有机膦配位聚合物衍生的富磷碳纳米材料及其储能应用

P-doped carbon materials, representing one of the most prominent families of heteroatom doped carbon materials, has exhibited huge application potential in the field of electrochemical energy storage and conversion, such as fuel cells, batteries, or supercapacitors. However, one of the great challenges for their practical applications is how to develop a facile approach for structure-controllable design of high-level P-doped content carbon nanomaterials. To address this challenge, a new strategy to design the p-doped carbon materials in this program is proposed, where high-level p-doped carbon materials will be prepared by in situ pyrolysis of Metal/Organic Phosphine Coordination Polymers (MOP-CPs) formed based on coordination self-assembly. The main objectives of this program is to reveal inheritance relationship between the precursors and the pyrolysis products by investigating the evolution of the morphologies and microstructures of MOP-CPs as well as understanding interactions of P, C and metal elements during the pyrolysis of MOP-CPs, and finally to come true the designable and controllable preparation of a variety of P-doped carbon materials with different morphologies and structures based on the MOP-CPs via designing the synthesizing conditions. Moreover, the P-doped carbon/metal phsophide composite nanostructures will be synthesized by utilizing P-Metal reaction via in-depth annealing during the pyrolysis of MOP-CPs. At last, the electrochemical energy storage performance of the MOP-CPs–derived P-doped carbon nanomaterials and P-doped carbon/metal phsophide composite nanostructures will be investigated preliminarily when used as anode materials for lithium/sodium ions batteries. Our work, employing the coordination self-assembly rules to tailor the MOP-CPs and designing MOP-CPs-derived P-doped carbon nanomaterials via pyrolysis, will not only broaden the application of MOP-CPs, but also be expected to develop a controllable and general pathway for advanced P-doped nanocarbons and their composites towards high-performance energy storage application.

磷掺杂碳材料在能源存储与转换领域展示出明显的优势，然而如何制备结构可控、高磷含量的碳材料是目前面临的挑战。本课题提出一种制备富磷碳材料的新理念，拟基于配位组装的原理设计金属/有机膦配位聚合物纳米结构作为前驱体，开展配位聚合物纳米结构的热解规律研究，揭示其微观结构以及磷元素掺杂状态在热解时的演变规律，阐明碳、磷、金属之间的相互作用机理，实现在分子水平上调控配位聚合物纳米构来设计富磷碳纳米材料的目标：一方面，制备结构及磷掺杂状态可控的富磷碳纳米材料；另一方面，通过磷与金属反应控制合成磷掺杂碳包覆金属磷化物复合纳米材料。进而考察所制备材料的储锂/钠性能，揭示磷原子对于储锂/钠性能的作用和储能构效关系，优化设计高性能的电化学储能材料。本课题将配位组装原理用于磷掺杂碳前驱体的调制，拓宽了有机膦配位聚合物的研究领域和应用范围，为设计结构新颖、高掺杂含量的富磷碳材料，提供了一条简单可控的新途径。

富磷碳材料在锂/钠离子电池、燃料电池等能源存储器件中，均显示出良好的应用前景，成为新的研究热点。然而，实现高效、可控、环境友好的富磷碳材料的合成，仍然充满挑战。本项目提出以金属/有机膦配位聚合物（MOPFs）衍生富磷碳材料的新方法。首先，以PTA、DPPE等有机膦为配体、过渡金属化合物为金属中心，开展了配位组装研究，设计了MOPFs纳米结构。然后，以MOPFs为前驱体，开展热解规律研究。MOPFs的有机膦配体可同时作为磷源和碳源，无需外加磷源，通过控制热解工艺条件即可合成一系列的富磷碳材料，包括：磷杂化碳材料、炭/过渡金属磷化物复合材料以及磷配位单原子金属掺杂碳材料。最后，在此基础上，以富磷碳材料为研究对象其储钠应用研究，探明结构与性能的构效关系，设计制备出高容量、高倍率性能、长周期循环稳定成的碳包覆金属晶电极材料。该方法与现有富磷碳材料的制备方法相比较，还有如下优势：（1）有机膦配体的配位模式丰富可调，即使只用一种多齿有机膦配体，选择合适的金属配位中心和合成条件，也能组装出多种形貌、结构、组成等可控的配位聚合物，从而实现从有机膦化物到富磷碳材料的分子水平设计；（2）配位聚合物中，金属呈原子级分散，有利于形成单原子金属以及金属磷化物高度分散的复合材料；（3）未与金属反应的磷原子将均匀、充分地掺杂在炭基体中，有效提高磷掺杂含量和分布状态，进而选择含多种杂原子的有机膦配体即可得到多原子掺杂的富磷碳材料。