摘要
Lithium metal batteries(LMBs)are considered the ideal next-generation high-energy-density systems,capable of surpassing the performance of lithium-ion batteries(LIBs).However,LMBs suffer from issues such as irreversible Li deposition/stripping,dendrite growth and significant volume fluctuations.Here,we use doctor blade coating to precisely control the loading of the bulk hard carbon(BHC)host with closed nanopores on carbon-coated copper(CCu)foil to achieve optimal cycling stability and rate performance for Li metal and anode-free battery systems.Through ex/in-situ techniques,we demonstrate that the BHC host induces a continuous intercalation-deposition mechanism,where the pre-lithiated BHC(preliBHC)phase,formed by Li+intercalation,improves Li affinity,accelerates Li+transport,and reduces nucleation overpotential,resulting in uniform Li deposition and effectively suppressing dendrite growth.Furthermore,these characterizations reveal that irreversible Li deintercalation from graphite layers is a key factor leading to the low initial Coulombic efficiency(ICE).Consequently,when coupled with a LiFePO_(4)cathode,the BHC-based full cell retains 96.3% of its capacity after 210 cycles at 1 C,demonstrating exceptional cycling stability.Notably,at-20℃,the full cell maintains 94.2% capacity retention after 60 cycles.These findings deepen the understanding of regulating Li metal deposition mechanisms and offer valuable insights into designing Li metal hosts for improved cycle life and high-rate performance.
基金
supported by the National Key Research and Development Program of China(2022YFE0109400)
Leading Edge Technology of Jiangsu Province(BK20220009,BK20232022)
Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
Center for Microscopy and Analysis at Nanjing University of Aeronautics and Astronautics。
