Integrated Gradient Cu Current Collector Enables Bottom‐Up Li Growth for Li Metal Anodes: Role of Interfacial Structure

Abstract

Abstract3D Cu current collectors have been demonstrated to improve the cycling stability of Li metal anodes, however, the role of their interfacial structure for Li deposition pattern has not been investigated thoroughly. Herein, a series of 3D integrated gradient Cu‐based current collectors are fabricated by the electrochemical growth of CuO nanowire arrays on Cu foil (CuO@Cu), where their interfacial structures can be readily controlled by modulating the dispersities of the nanowire arrays. It is found that the interfacial structures constructed by sparse and dense dispersion of CuO nanowire arrays are both disadvantageous for the nucleation and deposition of Li metal, consequently fast dendrite growth. In contrast, a uniform and appropriate dispersity of CuO nanowire arrays enables stable bottom Li nucleation associated with smooth lateral deposition, affording the ideal bottom‐up Li growth pattern. The optimized CuO@Cu‐Li electrodes exhibit a highly reversible Li cycling including a coulombic efficiency of up to ≈99% after 150 cycles and a long‐term lifespan of over 1200 h. When coupling with LiFePO4 cathode, the coin and pouch full‐cells deliver outstanding cycling stability and rate capability. This work provides a new insight to design the gradient Cu current collectors toward high‐performance Li metal anodes.

Gradient Host for Bottom-Up Deposition of Lithium Metal Anode

“…A dendrite-free Li anode is very important for long-cycle-life LMBs. − Therefore, another purpose of the Li metal anode hosts is to create the Li deposition sites and growth form according to the demands through the adjustability of the hosts themselves, to inhibit the formation of Li dendrites and dead Li. , The “bottom-up” Li deposition method is necessary since it can deposit Li metal preferentially at the bottom of the hosts, avoiding Li plating at the top of the anode, which can cause dendrites to split the separators and even produce dead Li and battery failure. , Figures c and d compare the electrochemical behavior of Li deposition/stripping in conventional and gradient hosts. For the insulating Li hosts, the bottom near the current collector is the only electron transport channel, which enables the Li metal to be preferentially deposited at the bottom of hosts.…”

“…67,68 The "bottom-up" Li deposition method is necessary since it can deposit Li metal preferentially at the bottom of the hosts, avoiding Li plating at the top of the anode, which can cause dendrites to split the separators and even produce dead Li and battery failure. 69,70 Figures 1c and 1d compare the electrochemical behavior of Li deposition/stripping in conventional and gradient hosts. For the insulating Li hosts, the bottom near the current collector is the only electron transport channel, which enables the Li metal to be preferentially deposited at the bottom of hosts.…”

Advanced engineering strategies for Li2S cathodes in lithium–sulfur batteries

“…This success has led to further research, resulting in various nanostructured Li 2 S-based host material composites, including carbon-based nanofibers, graphene papers, porous carbon materials, carbon-based nanocages, and porous organic conductive polymers, all crafted via solvent evaporation. 67,69,70,79,84,100–102…”

Stabilizing Lithium-Metal Host Anodes by Covalently Binding MgF2 Nanodots to Honeycomb Carbon Nanofibers

“…The potential of Li metal as the anode material for next-generation high-energy batteries has been widely recognized, given its ultrahigh theoretical capacity (3860 mAh g –1 ) and low electrochemical potential (−3.04 V vs the standard hydrogen electrode). − However, the challenges associated with Li dendrites’ notorious growth and the uncontrolled volume expansion during the repeated Li plating/stripping process are significant. These issues can lead to short circuits and even explosions, making the practical application of Li metal anodes a daunting task. , To date, various attempts have been made to regulate the Li plating/stripping performance, focusing on avoiding uncontrolled dendrite formation and volume expansion .…”