An Interlayer Containing Dissociated LiNO3 with Fast Release Speed for Stable Lithium Metal Batteries with 400 Wh kg−1 Energy Density

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-06, Vol.18 (25), p.e2202349-n/a
• Main Authors: Yang, Huicong, Liu, Qingyun, Wang, Yaozu, Ma, Zhuoting, Tang, Pei, Zhang, Xiaoyin, Cheng, Hui‐Ming, Sun, Zhenhua, Li, Feng
• Format: Article
• Language: English
• Subjects: Batteries; carbonate electrolyte; Cycles; Dendritic structure; dissociated state of LiNO 3; Electrode materials; Electrolytes; fast release rate; interlayer; Interlayers; Lithium; Lithium batteries; lithium metal anode; Nanotechnology; Performance enhancement; Polyvinyl chloride; Rechargeable batteries; Solid electrolytes
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202202349

Lithium metal is an ideal electrode material for future rechargeable batteries. However, dendrite formation and unstable solid electrolyte interphase film lead to safety concerns and poor Coulombic efficiency (CE). LiNO3 significantly improves the performance of the lithium metal anode in ester electrolytes but its use is restricted by low solubility. To increase the content of LiNO3 in the cell, a poly‐(vinyl carbonate) organogel interlayer containing dissociated LiNO3 (LNO‐PVC) is placed between the cathode and anode. The dissociated LiNO3 effectively increases the LiNO3‐release rate and compensates for the LiNO3 consumed in ester electrolytes during cycling. Via this interlayer, the performance of the lithium metal anode is significantly improved. The average CE of a Li‐Cu cell reaches 98.6% at 0.5 mA cm−2‐1 h and 98.5% at 1 mA cm−2‐1 h for 300 cycles. Also, a Li||NCM811 pouch cell with LNO‐PVC interlayer can also reach a 400 Wh kg−1 energy density with a cycling life of 65 cycles. This strategy sheds light on the effect of the state of this salt on its release/dissolution kinetics, which is determined by the interactions between the salt and host material. By using PVC as a host material, LiNO3 can exist in a dissociated state inside PVC rather than in a crystalline state. The dissociated LiNO3 has a lower activation energy for the dissolution/release process and realizes a fast release speed to ensure its efficient reduction on the lithium metal anode side to improve the battery performance.