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Practical Lithium-Sulfur Battery Technology
About
The on-going problem of atmospheric pollution due to the burning of fossil fuels has not yet been effectively solved, though some progress has been made. Currently, the most promising of the alternative energy sources are wind and solar. However, as is well known, both of these energy sources are intermittent and will require the development of highly efficient energy storage devices before wind and solar energy can replace fossil fuels as a the primary energy supply for the planet. Improved battery technology is therefore crucial for the future of clean, economical and reliable energy production. There have been significant advances in battery technology in the last thirty years, however, battery technology still has a long way to go before batteries will be a completely satisfactory storage medium for energy derived from solar and wind power. The primary problem with the current electrical battery technology is that it can't store enough energy in a small enough space. One of the most promising new battery technologies is the Lithium-Sulfur Battery, which has a capacity of almost ten times that of Lithium Ion batteries now in use. However, the Lithium-Sulfur battery has a significant drawback, a technical problem known as the sulfur shuttle phenomenon. A new invention is aimed at eliminating the problem and promises to be a breakthrough that will make the Lithium-Sulfur battery truly economical.
Key Benefits
* This is the first invention combining both ALD and MLD for tackling technical issues in Li-S batteries. * In this invention, the combination of ALD and MLD is a smart strategy in inhibiting S shuttling behaviors and improving S conductivities with the minimum additives. * Thoroughly eliminating S shuttling behaviors in Li-S batteries, this invention makes Li-S batteries reliable in Coulombic efficiency and long-term cyclability. * Besides inhibiting S loss, the smartly dual protection in this invention greatly improve the conductivities of the S cathodes and therefore enable high rate capabilities of the Li-S batteries. * With the uses of ALD and MLD in this invention, it enables a dramatic reduction in the addition of non-active materials, then boost the electroactive S mass ratio, and ultimately renders a much higher energy density of the resultant Li-S batteries. The strategy in this invention is simple and easy to scale up. The strategy can work directly on refabricated S cathodes. The advantages of this invention lies in the following ways: * Based on ALD and MLD, a dual protection strategy for the first time has been invented for effectively eliminating sulfur shuttling in Li-S batteries. ALD is used for depositing inorganic adsorbents in nanoparticles and MLD is employed to grow a close conductive film outside the S cathode materials. The two functional materials (i.e., the Sadsorbent nanoparticles and the conductive polymeric nanofilms) can work synergically for thoroughly inhibiting the S shuttle behaviors in Li-S batteries. Consequently, the resultant Li-S batteries also are reliable in cyclability and Coulombic efficiency. * In this invention, ALD and MLD enable accurately optimizing the addition of the Sadsorbents and conductive polymeric films to the minimum amount for the highest performance of Li-S batteries. In other words, this invention enables S cathodes with much higher S loadings and thereby a much higher energy density of Li-S batteries. * This invention is capable of higher ionic and electrical conductivities of S cathodes and enables high rate capabilities of Li-S batteries. Besides anchoring soluble polysulfides, the ALD-deposited S-adsorbents can serve as mediators of the S active materials for improved electrical and ionic conductivity. In addition to behaving like a flexible reservoir of polysulfides, on the other hand, the MLD-grown conductive polymeric films act as a conductive network to boost the electrical conductivity of the S cathode. As a result, this invention is likely to address the technical issues adversely plaguing LiS batteries, and is highly expected to eliminate S loss while realize the cell specific energy density of > 1500 Wh/kg, five to ten times over the state-of-the-art lithium-ion batteries.
Applications
* Portable electronics such as cell phones and laptops * Transportation (e.g., electric vehicle) * Smart grids * Autonomous devices (e.g., pacemakers)