浙江工业大学刘育京团队报道了基于氟化聚合物的三周期极小表面结构界面相强化高能锂金属电池。相关研究成果发表在2024年3月5日出版的国际学术期刊《德国应用化学》。

在锂（Li）阳极上构建机械坚固且重量轻的人造固体电解质界面层的挑战，凸显了高电池安全性和高能量密度之间的权衡。

受白海胆复杂微观结构的启发，研究人员首先开发了一种具有三周期最小表面结构（TPMS）的聚氟乙烯-六氟丙烯（PVDF-HFP）界面层，该界面层可以以最小的重量提供最大的模量。这种有序的多孔结构设计赋予了高的机械强度，有效地降低了局部电流密度、极化和内阻，并稳定了阳极界面。

在约3的低N/P比下，使用LiFePO₄作为阴极，由TPMS结构PVDF-HFP保护的Li阳极在1C下的200次循环中，实现了约0.002%的极低容量衰减率，平均放电容量为142mAh g^-1。同时，TPMS多孔结构节省了50wt%的界面层质量，从而提高了电池的能量密度。TPMS结构有利于大规模增材制造，这将为未来轻量化、高能量密度二次电池的发展提供参考。

附：英文原文

Title: A Triply-Periodic-Minimal-Surface Structured Interphase based on Fluorinated Polymers Strengthening High-energy Lithium Metal Batteries

Author: Cong Ma, Shihui Zou, Yuxuan Wu, Ke Yue, Xiaohan Cai, Yao Wang, Jianwei Nai, Tianqi Guo, Xinyong Tao, Yujing Liu

Issue&Volume: 2024-03-05

Abstract: The challenge of constructing a mechanically robust yet lightweight artificial solid-electrolyte interphase layer on lithium (Li) anodes highlights a trade-off between high battery safety and high energy density. Inspired by the intricate microstructure of the white sea urchin, we first develop a polyvinyl fluoride-hexafluoropropylene (PVDF-HFP) interfacial layer with a triple periodic minimal surface structure (TPMS) that could offer maximal modulus with minimal weight. This design endows high mechanical strength to an ordered porous structure, effectively reduces local current density, polarization, and internal resistance, and stabilizes the anode interface. At a low N/P ratio of ~ 3, using LiFePO4 as the cathode, Li anodes protected by TPMS-structured PVDF-HFP achieve an extremely low capacity-fading-rate of approximately 0.002% per cycle over 200 cycles at 1 C, with an average discharge capacity of 142 mAh g1. Meanwhile, the TPMS porous structure saves 50 wt.% of the interfacial layer mass, thereby enhancing the energy density of the battery. The TPMS structure is conducive to large-scale additive manufacturing, which will provide a reference for the future development of lightweight, high-energy-density secondary batteries.

DOI: 10.1002/anie.202402910

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202402910