State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, P. R. China.
Fujian Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, P. R. China.
Nat Commun. 2023 Jun 19;14(1):3639. doi: 10.1038/s41467-023-39391-8.
Stable lithium metal negative electrodes are desirable to produce high-energy batteries. However, when practical testing conditions are applied, lithium metal is unstable during battery cycling. Here, we propose poly(2-hydroxyethyl acrylate-co-sodium benzenesulfonate) (PHS) as negative electrode protective layer. The PHS contains soft poly (2-hydroxyethyl acrylate) and poly(sodium p-styrene sulfonate), which improve electrode flexibility, connection with the Cu current collector and transport of Li ions. Transmission electron cryomicroscopy measurements reveal that PHS induces the formation of a solid electrolyte interphase with a fluorinated rigid and crystalline internal structure. Furthermore, theoretical calculations suggest that the -SO group of poly(sodium p-styrene sulfonate) promotes Li-ion motion towards interchain migration through cation-dipole interaction, thus, enabling uniform Li-ion diffusion. Electrochemical measurements of Li | |PHS-coated-Cu coin cells demonstrate an average Coulombic efficiency of 99.46% at 1 mA/cm, 6 mAh/cm and 25 °C. Moreover, when the PHS-coated Li metal negative electrode is paired with a high-areal-capacity LiNiCoMnO-based positive electrode in multi-layer pouch cell configuration, the battery delivers an initial capacity of 6.86 Ah (corresponding to a specific energy of 489.7 Wh/kg) and, a 91.1% discharge capacity retention after 150 cycles at 2.5 mA/cm, 25 °C and 172 kPa.
稳定的金属锂负极是制备高能量电池的理想选择。然而，当实际测试条件应用时，金属锂在电池循环过程中不稳定。在这里，我们提出了聚（2-羟乙基丙烯酸酯-co-苯磺酸钠）（PHS）作为负极保护层。PHS 含有柔软的聚（2-羟乙基丙烯酸酯）和聚（苯乙烯磺酸钠），这提高了电极的柔韧性、与铜集流器的连接性和锂离子的传输性。透射电子冷冻显微镜测量显示，PHS 诱导了具有氟化刚性和结晶内部结构的固体电解质界面的形成。此外，理论计算表明，聚（苯乙烯磺酸钠）中的 -SO3 基团通过阳离子偶极相互作用促进锂离子向链间迁移，从而实现均匀的锂离子扩散。Li | |PHS 涂层-Cu 扣式电池的电化学测量表明，在 1 mA/cm、6 mAh/cm 和 25°C 下，平均库仑效率为 99.46%。此外，当 PHS 涂层的金属锂负极与高面积容量的 LiNiCoMnO 基正极在多层袋式电池结构中配对时，电池在 2.5 mA/cm、25°C 和 172 kPa 下，经过 150 次循环后，初始容量为 6.86 Ah（对应的比能量为 489.7 Wh/kg），放电容量保留率为 91.1%。
