纳米颗粒 FeF2@C 作为锂电池转换阴极,ACS Applied Energy Materials

当前位置： X-MOL 学术 › ACS Appl. Energy Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

纳米颗粒 FeF2@C 作为锂电池转换阴极
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2022-10-28 , DOI: 10.1021/acsaem.2c01988
Bryan R. Wygant ₁ , Noah B. Schorr ₁ , Igor V. Kolesnichenko ₁ , Timothy N. Lambert ₁

Affiliation

二氟化铁 (FeF ₂ ) 的高理论容量 (571 mAh/g) 和能量密度 (1519 Wh/kg) 使其成为用于锂基电池的有前途的转换阴极材料，提供了与材料导电性和反应性相关的固有限制是可以克服的。在这项工作中，我们报告了一种简单的合成方法，可生产直径约 35 nm 的结晶 FeF ₂颗粒，周围环绕着薄碳壳 (FeF ₂ @C)，并展示了其作为锂金属电池阴极的卓越性能。_{FeF 2} @C的表征表明，C 壳层厚度为 2–3 nm，由无定形共轭碳组成，氮含量为 3.8%，主要以吡啶部分的形式存在。当与锂金属负极配对时，FeF₂ @C 复合阴极表现出优异的比容量和保持力，在 C/20 下循环 50 次后为 634 mAh/g _FeF2@C ，而使用包含商用 FeF ₂的阴极时为 234 mAh/g _FeF2。该材料还表现出出色的倍率性能，并且在 1C 充电/放电速率下，表现出比普通插层阴极（如 LiFePO ₄ ）更大的容量。我们将 FeF ₂ @C 的性能归因于由于纳米级 FeF ₂颗粒而改善的锂化/脱锂行为、增强的化学和电化学损伤保护、C 壳层赋予的改善的导电性和容量，以及原位的额外容量循环过程中 FeF _{3的形成。}电化学循环后，FeF ₂ @C 材料的异位分析表明，虽然在颗粒表面形成了大约 2–8 nm 的阴极电解质界面 (CEI)，但底层材料保留了其初始纳米结构和 FeF ₂特性。

"点击查看英文标题和摘要"

Nanoparticulate FeF2@C as a Li Battery Conversion Cathode

The high theoretical capacity (571 mAh/g) and energy density (1519 Wh/kg) of iron difluoride (FeF₂) make it a promising conversion cathode material for use in Li-based batteries, provided inherent limitations related to material conductivity and reactivity are surmountable. In this work, we report a simple synthesis to produce crystalline FeF₂ particles approximately 35 nm in diameter surrounded by a thin carbon shell (FeF₂@C) and demonstrate its excellent performance as a cathode in Li metal batteries. Characterization of the FeF₂@C shows that the C-shell is 2–3 nm thick and composed of amorphous conjugated carbon with a nitrogen content of 3.8%, largely in the form of pyridinic moieties. When paired with a Li metal anode, the FeF₂@C composite cathodes exhibit excellent specific capacity and retention, 634 mAh/g_FeF2@C after 50 cycles at C/20, compared to 234 mAh/g_FeF2 when a cathode containing commercial FeF₂ was used. The material also shows excellent rate performance and, at a 1C charge/discharge rate, demonstrates a capacity greater than that of common intercalation cathodes like LiFePO₄. We attribute the performance of the FeF₂@C to improved lithiation/delithiation behavior due to the nanoscale FeF₂ particles, increased protection from chemical and electrochemical damage, improved conductivity and capacity granted by the C-shell, and additional capacity from the in situ formation of FeF₃ during cycling. After electrochemical cycling, ex situ analysis of the FeF₂@C material shows that while a roughly 2–8 nm cathode electrolyte interphase (CEI) forms on the surface of the particles, the underlying material retains its initial nanostructure and FeF₂-characteristics.

更新日期：2022-10-28

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南