高性能、长寿命的溴基液流电池正极材料的设计| Science Bulletin

文章

20

22

速递

Lamella-like electrode with high Br₂-entrapping capability and activity enabled by adsorption and spatial confinement effects for bromine-based flow battery

Luyin Tang, Tianyu Li, Wenjing Lu, Xianfeng Li

Science Bulletin, 2022, 67(13): 1362–1371

doi: 10.1016/j.scib.2022.05.012

简介

溴基液流电池(Br-FBs)具有能量密度高、成本低的优势, 在分布式储能领域具有良好的应用前景. 但其功率密度和寿命受限于溴电对反应活性较低、溴扩散导致电池自放电等问题. 为此, 研究人员利用具有吸附效应和空间限域效应的类层状多孔氮化碳纳米片(PCNS)来修饰碳毡电极(CF-PCNS), 并用于溴基液流电池正极材料. PCNS具有较大的比表面积和丰富的含氮基团, 可以将溴吸附在其层间的孔中. 同时, 基于溴与含氮基团之间的强相互作用和层状多孔结构的空间限域效应, 捕获的溴物种限制于PCNS层间, 从而有效抑制了溴的扩散. 此外, PCNS的强溴吸附能力显著提高了CF-PCNS的电化学活性. 因此, 以CF-PCNS为正极组装的锌溴流电池(ZBFB)可以在160 mA cm⁻² 下稳定循环500圈, 库伦效率可达99.22%, 且循环后容量保持率高达99.95%. 此外, 基于CF-PCNS优异的固溴的能力, 无络合剂的ZBFB得以实现, 且显示出优异的性能. 因此, 该工作为高性能和长寿命的Br-FBs用正极材料的设计提供了一种新的思路.

图文导读

Scheme 1 Illustrative diagram of adsorption and spatial confinement effects of CF-PCNS cathode.  

Fig. 1  (a) Schematic illustration of the fabrication of PCN and PCNS. SEM images of (b) PCN and (c) PCNS. (d) The XRD patterns of PCN and PCNS. TEM images of (e) PCN and (f) PCNS. (g) Pore-size distribution curves of PCN and PCNS. (h) EDS mappings for PCNS.

Fig. 2  (a) High-resolution N 1s XPS spectra of PCN and PCNS. (b) The DEs of bromine molecule on different electrode surfaces. (c) Bromine adsorption behaviors of PCN and PCNS. (d) The optimal structures of PCN and PCNS surface absorb bromine molecule (Brown spheres: C atoms; Gray spheres: N atoms; Cyan spheres: Br atoms). (e) High-resolution N 1s of PCNS and PCNS-Br₂. (f) High-resolution C 1s of PCNS and PCNS-Br₂. (g) FTIR spectra of PCNS and PCNS-Br₂.

Fig. 3  (a) CV curves of PCF, CF-PCN, and CF-PCNS at the scan rate of 10 mV s⁻¹. (b) CV curves of PCF, CF-PCN and CF-PCNS at the scan rate of 10 mV s⁻¹ and in an acidic electrolyte to eliminate the effect of oxygen evolution. (c) LSV curves (scan rate: 1 mV s⁻¹) and (d) Nyquist plots of PCF, CF-PCN, and CF-PCNS.

Fig. 4  In-situ Raman spectra of one fixed point on the cathodes of ZBFBs during the (a) charge and (b) discharge process at different times.

Fig. 5  (a) Photos of the solution color change during charging. (b) Iring–t curves of different materials. (c) The catalytic mechanism of Br₂/Br⁻ couple on CFPCNS. (d) The synergy of adsorption and spatial confinement effects of PCNS to entrap bromine species tightly.

通讯作者

鲁文静 中国科学院大连化学物理研究所副研究员. 主要从事液流电池关键材料的设计开发.   

李先锋 中国科学院大连化学物理研究所研究员. 主要从事电化学储能技术特别是液流电池储能技术的基础研究和产业化开发工作.   

相关阅读

栏目介绍

论文 Article

报道具创新性和重要科学意义的最新科研成果(一般不超过10个印刷面，附250字左右摘要，4-6个关键词，图表不超过10个，参考文献不超过60条)。