Cycle Life Sensor for Rechargeable Lithium Batteries

在高电压下提供高能量密度的可再充电电源 在过去的二十五年里， 年 虽然许多有效的可再充电正极材料 (the阴极）在过去10年中不断发展， 开发一种实用的二次锂负极（阳极）， 慢了 这项技术发展缓慢的主要原因是 在于不能使Li电极在高容量下循环 在长时间内具有高效率。 这是因为 非质子有机溶剂和支持电解质盐， 与Li反应。 因此，一个主机的相对速率 竞争反应最终决定细胞周期寿命。 的目标 这项研究是双重的：确定哪些化学降解 产品最终会影响电池的安全性和循环寿命; 开发一种商业化的原位电分析传感器， 电池在沿着其循环寿命的任何点的状态。 电池 在一些配置中，单个循环寿命或电压受限的电池将 使系统不平衡，导致过早失效。 细胞状态 传感器将使最终用户能够简单地更换单个坏电池 而不是整个电池单元。 PI计划使用计算机控制的方波伏安法（SWV） 在两个或更多个微电极上，以获得关于 同质和异质细胞化学。 镍微电极， 嵌入在电池包中，将用于直接感测 Li/电解质反应性的性质和程度，作为 自行车历史 他们完全有资格完成这项工作， 设施足够。 建议提供第一阶段SBIR赠款。

Rechargeable power sources which provide high energy densities at high rates have been under active investigation for the past twenty-five years. While many effective rechargeable positive electrode materials (the cathode) have evolved over the past 10 years, progress in developing a practical secondary Li negative (the anode) has been slow. The principal reason for the slow evolution of this technology resides in the inability to cycle the Li electrode at high capacities with high efficiency over a long period of time. This is because aprotic organic solvents and supporting electrolyte salts are intrinsically reactive with Li. Thus, the relative rates of a host of competing reactions ultimately determine cell cycle life. The goal of this research is two-fold: to ascertain which chemical degradation products ultimately influence cell safety and cycle life; and to develop a commercial in situ electroanalytical sensor which specifies the state of a cell at any point along its cycle life. In battery configurations, a single cycle-life or voltage limited cell will unbalance the system causing premature failure. A state of cell sensor would enable the end user to simply replace a single bad cell rather than the entire battery unit. The PIs plan to use computer-controlled square wave voltammetry (SWV) at two or more microelectrodes to obtain information regarding homogeneous and heterogeneous cell chemistries. Ni microelectrodes, embedded in the cell package, will be used to directly sense the nature and degree of Li/electrolyte reactivity as a function of cycling history. They are well qualified to complete this work and their facilities are adequate. A Phase I SBIR grant is recommended.