Method for Preparing High-Energy Electrodes with Controlled Microstructures for Energy-Storage Devices
The current manufacturing methods for Lithium-Ion Batteries are limited to around 200 Wh/kg. Power density is a factor of the battery construction and is highly dependent on the electrodes.
Conventional Li-ion batteries consist of electrodes constructed of stacks of 70 µm films. The thin electrodes then require current collectors and separators for assembly, which increase mass without adding charge capacity. The need for these inactive components limits the power density of batteries as they add no storage capacity. Standard electrode film thickness is limited to around 100 µm because as thickness increases, the potential for ion transport across the electrode is reduced. Reduced ion transfer results in reduced power storage capacity and will also result in poor cycling characteristics over the life of the battery.
This technology describes a manufacturing method for producing thick electrodes for Li-ion batteries by controlling porosity during construction. This is done by engineering cracks through the thickness of the electrode during manufacturing to allow for increased ion transport or charge capacity. The result is high energy capacity without the drawback of poor cycling characteristics. The inventor has demonstrated the ability to optimize the amount of cracking during production to limit power storage capacity reduction in typically seen in thicker electrodes.
This manufacturing technique could produce thick electrodes with high stability resulting in Lithium-Ion batteries with improved power density over thin film electrodes. It has extensive application in electric vehicles and grid connected energy storage systems
The technology produces thick electrodes, which can result in Li-ion batteries with power densities more than 300 Wh/kg. It also reduces construction costs by reducing the time required to assemble thinner electrodes. The production method is environmentally responsible, sustainable, and lowers waste disposal costs-- it replaces toxic n-methyl pyrrolidone with water, and uses Fluorine-free binders.