高强度、高孔容三维连续多孔铜膜集流体的可控设计及高密度复合储能研究

Reducing the lithium ion and electron transport path and improving the mass loading of active materials in the electrodes are keys to large-scale application of the nanoscale electrode materials toward high energy density lithium ion batteries (LIBs). This project takes copper current collector as the research object, studying on the mechanism of nonsolvent induce phase separation method (NIPS) and combining with sintering technology, achieving controllable preparation of continuous three-dimensional (3D) porous copper membrane with high strength and high pore capacity, and high density energy storage composite electrode will be obtain by attaching nanoscale active materials and combining of rolling technique. In this project, we mainly focuses on the study of 3D structure formation mechanism of organic-metal membrane and structure inheritance mechanism of copper membrane molding; exploring of the regulation mechanism of the experimental parameters on pore capacity, surface characteristics, plastic deformation and interfacial bonding strength of current collector and composite electrode; establishing of the structure-performance model between material structure and electrochemical properties; elaborating the mechanism of continuous 3D porous current collector to improve the energy storage density of electrode. Using this continuous 3D porous copper membrane as current collector, is expected to get high energy density composite electrode with short lithium ion and electron transport path, high space utilization and active material loading amount, good mechanical properties and conductivity, guiding for the fabrication of high energy density storage system for super long endurance.

缩短锂离子和电子在集流体与活性材料之间的输运路径、提高活性材料在电极中的负载量是纳米电极材料规模化应用的关键。本项目以铜集流体为研究对象，通过研究非溶剂致相分离原理并结合烧结技术，实现高强度、高孔容三维连续多孔铜膜的可控制备，并通过负载纳米活性材料结合轧制技术获得高密度复合储能电极。重点研究有机-金属复合膜三维结构成型机制和铜膜成型的结构继承机制；探究实验参数对集流体和复合储能电极的孔容、表面特性、塑性变形及界面结合强度的调控机制；建立材料结构与电化学性能间的构效模型；阐明三维连续多孔集流体对提高电极储能密度的机理。采用该三维连续多孔铜膜为集流体有望获得兼具短的锂离子/电子输运路径、高空间利用率和活性材料负载量、良好的力学性能和导电性的高密度复合储能电极，为发展超长续航能力的高密度储能电源提供借鉴和参考。

本项目面向新兴钠离子电池市场以及现有锂离子电池市场，跨越原有锂离子电池企业生产设备更新的难题，从源头上占领市场先机，为高能量密度高安全性锂/钠离子电池等新型储能系统提供全新的集流体解决方案。基于多孔金属膜的导电性、结构导热性和高效电子/离子输运的原理，解决锂/钠离子电池铜箔集流体无法实现高性能纳米粉体电极材料实用级应用的关键问题。本项目所开发的集流体产品在30-100 μm厚的限制范围被可覆载球磨后的纳米石墨4.4 mg/cm2，其循环稳定性同传统铜箔对纳米粉体电极材料的1 mg/cm2具有显著提升，相比于其他金属集流体产品，更能够满足新能源汽车等使用对电池的高体积能量密度的需求。基于三维多孔集流体的研究思路，本项目还开发了三维多孔镍、钛集流体基电极材料、纳米多孔合金基电极材料，并研究了活性电极材料的覆载机制，结合理论计算明确了电极材料的电化学的储能机理。另外，基于本项目的研究成果，项目负责人在产业化应用方面做出了初步的探索，以“多孔金属集流体的研发与产业化”为题参加了第一届全国博士后创新创业大赛总决赛创业赛并获得了新能源（含新能源汽车）组优胜奖。

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