Cycle Life Sensor for Rechargeable Lithium Batteries

在过去的25年里，人们一直在积极研究以高速率提供高能量密度的可充电电源。虽然许多有效的可充电正极材料（阴极）在过去的10年里得到了发展，但开发实用的二次锂负极（阳极）的进展缓慢。该技术发展缓慢的主要原因在于无法在很长一段时间内以高容量和高效率循环锂电极。这是因为非质子有机溶剂和支持电解质盐本质上与锂反应。因此，一系列相互竞争的反应的相对速率最终决定了细胞的周期寿命。这项研究的目的有两个：确定哪些化学降解产物最终会影响细胞的安全性和循环寿命；并开发一种商业化的原位电分析传感器，它可以指定电池在其循环寿命中任何一点的状态。在电池配置中，单个循环寿命或电压有限的电池会使系统失去平衡，导致过早失效。电池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计划在两个或多个微电极上使用计算机控制的方波伏安法（SWV）来获取有关均质和非均质细胞化学的信息。嵌入电池封装中的Ni微电极将用于直接感知Li/电解质反应性的性质和程度，作为循环历史的函数。他们完全有资格完成这项工作，他们的设施也足够。建议申请一期SBIR拨款。

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.