J.H. Sung, J-S Yu
Daegu Gyeongbuk Institute of Science and Technology,
Korea
Keywords: hollow carbon, anode-free, Li metal, anode
Summary:
Anode-free lithium (Li) metal batteries are recognized as one of the most efficient battery systems with full merits of high capacity (3860 mAh g-1) and low operating potential (-3.04 V vs standard hydrogen electrode) of Li. Removing the Li anode from rechargeable batteries can increase energy density and lower production costs. However, without continuous Li supply in the anode side, the anode-free design encounters huge challenges against high cycle stability. Herein, an N-doped hollow carbon framework (HCF) derived from zeolitic imidazolate framework (ZIF) is loaded with silver (Ag) as a lithiophilic element, and the resulting Ag@HCF casted on a copper (Cu) current collector (Ag@HCF/Cu) is proposed for stable Li deposition to achieve the long-term cycle life in anode-free batteries. The HCF has several advantages of N-doping, low weight, high specific surface area, and high electrical conductivity, which can help provide uniform Li nucleation and plating reaction and minimize energy density loss. In addition, Ag@HCF can effectively suppress the Li dendrite growth through uniform distribution of electrons. In this study, the Li-Ag@HCF/Cu, which is prepared using in-situ Li plating reaction delivers the low nucleation overpotential, reduced voltage hysteresis, and high average coulombic efficiency (ACE) at high current density up to 4 mA cm-2 under 4 mAh cm-2. Furthermore, in a full cell system which is assembled with LiNi0.5Co0.2Mn0.3O2 (NCM) cathode of 4 mAh cm-2 scale, Li-Ag@HCF/Cu||NCM cell reveals superior capacity retentions of 80.9% for 100 cycles and 66.0% for 300 cycles, which can become an effective cornerstone for stable anode-free Li metal batteries.