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High interfacial-energy interphase promoting safe lithium metal batteries
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2020-01-13 , DOI: 10.1021/jacs.9b11750
Sufu Liu 1, 2 , Xiao Ji 1 , Jie Yue 1 , Singyuk Hou 1 , Pengfei Wang 1 , Chunyu Cui 1 , Ji Chen 1 , Bowen Shao 3 , Jingru Li 2 , Fudong Han 3 , Jiangping Tu 2 , Chunsheng Wang 1
Affiliation  

Engineering a stable solid electrolyte interphase (SEI) is critical for suppression of lithium dendrites. However, formation of desired SEI by formulating electrolyte composition is very difficult due to complex electrochemical reduction reactions. Here, instead of try-and-error of electrolyte composition, we design a Li-11 wt% Sr alloy anode to form SrF2-rich SEI in fluorinated electrolytes. Density functional theory (DFT) calculation and experimental characterization demonstrate that SrF2-rich SEI has a large interfacial energy with Li metal and a high mechanical strength, which can effectively suppress the Li dendrite growth by simultaneously promoting the lateral growth of deposited Li metal and the SEI stability. The Li-Sr/Cu cells in 2M LiFSI-DME shows an outstanding Li plating/stripping Coulombic efficiency of 99.42% at 1 mA cm-2 with a ca-pacity of 1 mAh cm-2 and 98.95% at 3 mA cm-2 with a capacity of 2 mAh cm-2, respectively. The symmetric Li-Sr/Li-Sr cells also achieve a stable electrochemical performance of 180 cycles at an extremely high current density of 30 mA cm-2 with a capacity of 1 mAh cm-2. When paired with LiFePO4 (LFP) and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes, Li-Sr/LFP cells in 2M LiFSI-DME electrolytes and Li-Sr/NMC811 cells in 1M LiPF6 in FEC:FEMC:HFE electrolytes also maintain excellent capacity retention. Designing SEI by regulating Li metal anode composition opens up a new and rational avenue to suppress Li dendrites.

中文翻译:

高界面能界面促进安全锂金属电池

设计稳定的固体电解质界面(SEI)对于抑制锂枝晶至关重要。然而,由于复杂的电化学还原反应,通过配制电解质组合物来形成所需的 SEI 非常困难。在这里,我们设计了一个 Li-11 wt% Sr 合金阳极,以在氟化电解质中形成富含 SrF2 的 SEI,而不是反复尝试电解质组成。密度泛函理论 (DFT) 计算和实验表征表明,富含 SrF2 的 SEI 与锂金属的界面能大,机械强度高,可以通过同时促进沉积的锂金属和锂金属的横向生长来有效抑制锂枝晶的生长。 SEI 稳定性。2M LiFSI-DME 中的 Li-Sr/Cu 电池显示出出色的锂电镀/剥离库仑效率为 99。1 mA cm-2 时为 42%,容量为 1 mAh cm-2,3 mA cm-2 时为 98.95%,容量为 2 mAh cm-2。对称的 Li-Sr/Li-Sr 电池还在 30 mA cm-2 的极高电流密度下实现了 180 次循环的稳定电化学性能,容量为 1 mAh cm-2。当与 LiFePO4 (LFP) 和 LiNi0.8Co0.1Mn0.1O2 (NCM811) 正极配对时,2M LiFSI-DME 电解质中的 Li-Sr/LFP 电池和 FEC:FEMC:HFE 电解质中 1M LiPF6 中的 Li-Sr/NMC811 电池保持出色的容量保持率。通过调节锂金属负极组成来设计 SEI 为抑制锂枝晶开辟了一条新的合理途径。对称的 Li-Sr/Li-Sr 电池还在 30 mA cm-2 的极高电流密度下实现了 180 次循环的稳定电化学性能,容量为 1 mAh cm-2。当与 LiFePO4 (LFP) 和 LiNi0.8Co0.1Mn0.1O2 (NCM811) 正极配对时,2M LiFSI-DME 电解质中的 Li-Sr/LFP 电池和 FEC:FEMC:HFE 电解质中 1M LiPF6 中的 Li-Sr/NMC811 电池保持出色的容量保持率。通过调节锂金属负极组成来设计 SEI 为抑制锂枝晶开辟了一条新的合理途径。对称的 Li-Sr/Li-Sr 电池还在 30 mA cm-2 的极高电流密度下实现了 180 次循环的稳定电化学性能,容量为 1 mAh cm-2。当与 LiFePO4 (LFP) 和 LiNi0.8Co0.1Mn0.1O2 (NCM811) 正极配对时,2M LiFSI-DME 电解质中的 Li-Sr/LFP 电池和 FEC:FEMC:HFE 电解质中 1M LiPF6 中的 Li-Sr/NMC811 电池保持出色的容量保持率。通过调节锂金属负极组成来设计 SEI 为抑制锂枝晶开辟了一条新的合理途径。
更新日期:2020-01-13
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