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High‐Coulombic‐Efficiency Carbon/Li Clusters Composite Anode without Precycling or Prelithiation
Small ( IF 13.0 ) Pub Date : 2018-07-20 , DOI: 10.1002/smll.201802226
Ran Tian 1 , Huanan Duan 1 , Yiping Guo 1 , Hua Li 1 , Hezhou Liu 1
Affiliation  

Lithium metal has attracted much research interest as a possible anode material for high‐energy‐density lithium‐ion batteries in recent years. However, its practical use is severely limited by uncontrollable deposition, volume expansion, and dendrite formation. Here, a metastable state of Li, Li cluster, that forms between LiC6 and Li dendrites when over‐lithiating carbon cloth (CC) is discovered. The Li clusters with sizes in the micrometer and submicrometer scale own outstanding electrochemical reversibility between Li+ and Li, allowing the CC/Li clusters composite anode to demonstrate a high first‐cycle coulombic efficiency (CE) of 94.5% ± 1.0% and a stable CE of 99.9% for 160 cycles, which is exceptional for a carbon/lithium composite anode. The CC/Li clusters composite anode shows a high capacity of 3 mAh cm−2 contributed by both Li+ intercalation and Li‐cluster formation, and excellent cycling stability with a signature sloping voltage profile. Furthermore, the CC/Li clusters composite anode can be assembled into full cells without precycling or prelithiation. The full cells containing bare CC as the anode and excessive LiCoO2 as the cathode exhibit high specific capacity and good cyclic stability in 200 cycles, stressing the advantage of controlled formation of Li clusters.

中文翻译:


无需预循环或预锂化的高库仑效率碳/锂团簇复合阳极



近年来,锂金属作为高能量密度锂离子电池的可能负极材料引起了广泛的研究兴趣。然而,其实际应用受到不可控沉积、体积膨胀和枝晶形成的严重限制。在这里,当发现过度锂化的碳布(CC)时,Li的亚稳态,即Li簇,在LiC 6和Li枝晶之间形成。尺寸在微米和亚微米尺度的Li团簇在Li +和Li之间具有出色的电化学可逆性,使得CC/Li团簇复合负极表现出高达94.5%±1.0%的首次循环库仑效率(CE)和稳定的稳定性。 160 次循环的 CE 值为 99.9%,这对于碳/锂复合阳极来说是非常出色的。 CC/Li团簇复合阳极表现出由Li +嵌入和Li团簇形成共同贡献的3 mAh cm -2的高容量,以及具有标志性倾斜电压分布的优异循环稳定性。此外,CC/Li团簇复合阳极可以组装成全电池,无需预循环或预锂化。含有裸CC作为阳极和过量LiCoO 2作为阴极的全电池在200次循环中表现出高比容量和良好的循环稳定性,强调了控制Li团簇形成的优势。
更新日期:2018-07-20
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