Soni Roby, Spadoni Damiano, Shearing Paul R, Brett Dan J L, Lekakou Constantina, Cai Qiong, Robinson James B, Miller Thomas S
Department of Chemical Engineering, Electrochemical Innovation Lab, University College London, London WC1E 7JE, U.K.
The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot OX11 0RA, U.K.
ACS Appl Energy Mater. 2023 May 31;6(11):5671-5680. doi: 10.1021/acsaem.2c04131. eCollection 2023 Jun 12.
It is widely accepted that the commercial application of lithium-sulfur batteries is inhibited by their short cycle life, which is primarily caused by a combination of Li dendrite formation and active material loss due to polysulfide shuttling. Unfortunately, while numerous approaches to overcome these problems have been reported, most are unscalable and hence further hinder Li-S battery commercialization. Most approaches suggested also only tackle one of the primary mechanisms of cell degradation and failure. Here, we demonstrate that the use of a simple protein, fibroin, as an electrolyte additive can both prevent Li dendrite formation and minimize active material loss to enable high capacity and long cycle life (up to 500 cycles) in Li-S batteries, without inhibiting the rate performance of the cell. Through a combination of experiments and molecular dynamics (MD) simulations, it is demonstrated that the fibroin plays a dual role, both binding to polysulfides to hinder their transport from the cathode and passivating the Li anode to minimize dendrite nucleation and growth. Most importantly, as fibroin is inexpensive and can be simply introduced to the cell via the electrolyte, this work offers a route toward practical industrial applications of a viable Li-S battery system.
人们普遍认为，锂硫电池的商业应用受到其短循环寿命的限制，这主要是由锂枝晶形成以及多硫化物穿梭导致的活性物质损失共同造成的。不幸的是，尽管已经报道了许多克服这些问题的方法，但大多数方法都无法规模化，因此进一步阻碍了锂硫电池的商业化。大多数提出的方法也只解决了电池降解和失效的主要机制之一。在这里，我们证明，使用一种简单的蛋白质——丝素蛋白作为电解质添加剂，既可以防止锂枝晶的形成，又能将活性物质的损失降至最低，从而在锂硫电池中实现高容量和长循环寿命（高达500次循环），同时又不影响电池的倍率性能。通过实验和分子动力学（MD）模拟相结合，证明了丝素蛋白具有双重作用，既能结合多硫化物以阻碍其从阴极传输，又能钝化锂阳极以最小化枝晶的成核和生长。最重要的是，由于丝素蛋白价格低廉且可以通过电解质简单地引入电池中，这项工作为可行的锂硫电池系统的实际工业应用提供了一条途径。
