In-Situ Cross-linked F- and P-Containing Solid Polymer Electrolyte for Long-Cycling and High-Safety Lithium Metal Batteries with Various Cathode Materials.

The practical application of lithium metal batteries (LMBs) has been hindered by limited cycle-life and safety concerns. To solve these problems, we develop a novel fluorinated phosphate cross-linker for gel polymer electrolyte in high-voltage LMBs, achieving superior electrochemical performance and high safety simultaneously. The fluorinated phosphate cross-linked gel polymer electrolyte (FP-GPE) by in-situ polymerization method not only demonstrates high oxidation stability but also exhibits excellent compatibility with lithium metal anode. LMBs utilizing FP-GPE realize stable cycling even at a high cut-off voltage of 4.6 V (vs Li/Li+) with various high-voltage cathode materials. The LiNi0.6Co0.2Mn0.2O2|FP-GPE|Li battery exhibits an ultralong cycle-life of 1200 cycles with an impressive capacity retention of 80.1 %. Furthermore, the FP-GPE-based batteries display excellent electrochemical performance even at practical conditions, such as high cathode mass loading (20.84 mg cm-2), ultrathin Li (20 µm), and a wide temperature range of -25 to 80 °C. Moreover, the first reported solid-state 18650 cylindrical LMBs have been successfully fabricated and demonstrate exceptional safety under mechanical abuse. Additionally, the industry-level 18650 cylindrical LiMn2O4|FP-GPE|Li4Ti5O12 cells demonstrate a remarkable cycle-life of 1400 cycles. Therefore, the impressive electrochemical performance and high safety in practical batteries demonstrate a substantial potential of well-designed FP-GPE for large-scale industrial applications.

An In Situ Fabricated Graphene/Bipolar Polymer Hybrid Material Delivers Ultralong Cycle Life over 15 000 Cycles as a High-Performance Electrode Material.

Organic electrode materials are promising for the future energy storage systems owing to their tunable structures, abundant resources, and environmental friendliness. Many advanced lithium-ion batteries with organic electrodes have been developed and show excellent performance. However, developing organic materials with overall superior performance still faces great challenges, such as low capacity, poor stability, inferior conductivity, and low utilization of active sites. To address these issues, a bipolar polymer (Fc-DAB) is designed and further polymerized in situ with three-dimensional graphene (3DG), offering a hybrid material (Fc-DAB@3DG) with a variety of merits. Fc-DAB possesses stable polymer backbone and multiple redox-active sites that can improve stability and capacity simultaneously. The embedded highly conductive 3DG network endows Fc-DAB@3DG with stable conductive framework, large surface area, and porous morphology all together, so the fast diffusion of ions/electrons can be achieved, leading to high utilization of active sites and enhanced electrochemical performance. As a result, Fc-DAB@3DG cathode delivers capacity of ≈260 mA h g-1 at 25 mA g-1 , ultra-long cycle life over 15 000 cycles at 2000 mA g-1 with retention of 99.999% per cycle, and remarkable rate performance. The quasi-solid Li-metal battery and full cell fabricated using this material also exhibit superior electrochemical performance.