3D打印策略实现超高面积能量密度锂-锌混合离子电池 | Science Bulletin

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3D printing of fast kinetics reconciled ultra-thick cathodes for high areal energy density aqueous Li–Zn hybrid battery

Hanna He, Dan Luo, Li Zeng, Jun He, Xiaolong Li, Huaibo Yu,Chuhong Zhang

Science Bulletin, 2022, 67(12): 1253–1263

doi: 10.1016/j.scib.2022.04.015

简介

水系混合离子电池因低成本、高安全性等优点在小型可穿戴电子产品中受到了广泛关注, 但是其有限的面积能量密度阻碍了其在微型储能器件中的应用. 构筑厚电极是实现高面积能量密度的一种有效策略, 但电极厚度增加所带来的离子/电子传输迟缓、机械柔性差等问题, 限制了传统厚电极的电化学能. 基于此,本文提出3D打印策略构筑兼顾超高活性物质负载和快速离子扩散动力学的磷酸铁锂(LFP)厚电极, 实现了超高面积能量密度锂-锌混合离子电池. 3D打印结构设计赋予电极规则宏观孔结构, 冷冻干燥进一步在结构中引入大量的微观孔, 为多级离子传输提供畅通无阻的扩散通道, 保证了电极在厚度增加的情况下快速的离子扩散动力学. 在该3D打印电极中, 均匀分散的碳纳米管(CNTs)和纤维素纳米纤维(CNFs)形成相互连通的三维网络结构, 均匀包裹住LFP活性材料, 既保证了快速的电子转移,又有效地消除了循环过程中电极的内应力. 得益于以上优势, 3D打印的超厚(2.08 mm)LFP/CNT/CNFs电极应用于锂–锌混合离子电池正极实现了创纪录的面积能量密度(5.25 mWh cm⁻²), 优于几乎所有报道的锌基混合离子、单离子电池和电容器. 这项工作为开发高面积能量密度储能器件提供了新思路.

图文导读

Fig. 1 (a) Schematic representation of 3D printing process of LFP-3DP electrode. (b) Apparent viscosity of LFP/CNT/CNF ink. (c) Storage modulus and loss modulus function as shear stress for LFP/CNT/CNF ink. (d) The thickness and loading density of electrodes with different printing layers.

Fig. 2. (a–h) Microscopic morphology, structure, and XRD patterns of LFP-3DP electrode: SEM images from (a) the top view, (b) a cross-sectional view, (c, d) magnified SEM images, (e) TEM image, (f) high-resolution TEM images, (g) HAADF image, and (h) EDS mapping images. (i) XRD patterns of LFP-3DP electrode and commercial LFP powder.

Fig. 3. (a) and (b) High-resolution XPS spectra of Li 1s and Fe 2p for LFP-3DP. (c) Raman spectra of LFP-3DP. (d, e) The contact angle test of LFP-3DP and LFP-C. (f) The electrical conductivity of LFP-3DP and LFP-C. (g) N₂ adsorption and desorption isotherms and pore size distributions of the LFP-3DP.

Fig. 4. (a) Charge and discharge profiles of the LFP-3DP and LFP-Bulk electrode with various layers. (b) Rate performance of the LFP-3DP and LFP-Bulk electrode. (c) Cycling performance of the LFP-3DP and LFP-Bulk electrode at 1 C. (d) SEM images of LFP-3DP before and after 100 cycles at 1 C.

Fig. 5 (a) and (b) CV curves of LFP-3DP-6 Layer and LFP-Bulk-6 Layer electrodes at different scan rates. (c) CV curves of the LFP-3DP-6 Layer and LFP-Bulk-6 Layer at the scan rate of 0.9 mV s⁻¹. (d) Electrochemical impedance spectroscopy (EIS) for LFP-3DP-6 Layer and LFP-Bulk-6 Layer electrodes. (e) GITT profiles for LFP-3DP-6 Layer and LFP-Bulk-6 Layer electrodes at 0.1 C. (f) Diffusion coefficients of LFP-3DP-6 Layer and LFP-Bulk-6 Layer electrodes calculated from the GITT results. (g) Ex-situ XRD patterns of LFP cathode against the Zn foil as anode collected at various states in the initial cycle at the rate of 0.2 C. (h) Illustration of charge/discharge process and ion/electron transportation behavior on Zn/LFP-3DP aqueous rechargeable battery.

Fig. 6. Electrochemical properties of Li–Zn hybrid pouch cell with various layered LFP-3DP electrodes as cathodes. (a) Charge and discharge profiles at 0.5 C. (b) Rate performance from 0.5 C to 20 C. (c) The relationship between areal energy density and gravimetric energy density. (d) The areal energy density of the LFP-3DP electrode compared to representative literatures. Digital photos of three Zn/LFP rechargeable aqueous hybrid batteries connected in series to light series of (e) light-emitting diodes (LEDs) and (f) a thermohygrometer.

通讯作者

张楚虹 四川大学高分子研究所教授. 主要从事高分子功能材料和器件先进制造的前沿基础和应用研究.   

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