Lithiophilic and Anticorrosive Cu Current Collector via Dual-Bonded Porous Polymer Coating for Stable Lithium-Metal Batteries

Abstract

Li metal is the ultimate anode material for nextgeneration high-energy-density rechargeable batteries. However, the uncontrollable growth of Li dendrites and low Coulombic efficiency (CE) prevent it from practical applications in Li metal batteries (LMBs). Here, a facile and low-cost strategy is developed to decorate a Cu current collector with a self-assembled γ-aminopropyltrimethoxysilane (γ-APS) film. The thin polymer film with nanopores promotes the formation of cobblestone-like Li deposition and suppresses Li-dendrite formation due to its low surface energy. The protecting layer not only increases the lithiophilicity of the Cu current collector but also alleviates the ambient corrosion and galvanic corrosion in practical use. Owing to these advantages, the half cell using γ-APS-Cu collectors exhibits a high average CE value of 99.2% for 100 cycles. The symmetric cell of γ-APS-Cu@Li shows an improved lifespan of 1400 h with a small voltage hysteresis of 12 mV at 0.5 mA cm −2 . The full cell assembled with LiFePO 4 (LFP) cathodes and γ-APS-Cu@Li anodes delivers a high capacity of 136 mAh g −1 after 600 cycles at 0.5C.

Copper Current Collector: The Cornerstones of Practical Lithium Metal and Anode–Free Batteries

“…Typical examples are high concentration electrolyte, weakly solvating electrolyte, nitrogen-containing additives and fluorine-containing additives. [23][24][25][26] Another method is current collector optimization, which includes regulating the Li affinity of substrate, [27,28] surface passivation treatment to reduce side reactions, [29,30] constructing fast ion channels, [31,32] increasing reaction area to reduce Li + deposition rate [3,22] etc., and all these approaches has been summarized as "3D structure", "lithophiilc modification" and "building ASEI" in Figure 1. Nowadays, some currentcollector technology already exhibited some practicability.…”