Porous array of BaLi4 alloy microchannels enforced carbon cloth for a stable Li composite anode

Abstract

Integrating metallic lithium (Li) with a three-dimensional (3D) host is a popular strategy for long-life Li composite anodes, where the structure and physicochemical nature of the framework are critical for the electrochemical performance. Herein, Li-rich dual-phase barium (Ba)-based alloy composed of BaLi4 intermetallic compounds and Li metal phases is thermally incorporated into commercial carbon cloth sheets to develop Li-Ba alloy composite (LBAC) anodes featuring a porous array of BaLi4 microchannels as the built-in 3D skeleton. Doping of metallic Ba can greatly lower the surface tension of liquid Li and improve the wettability of the molten Li-Ba alloy toward the carbon cloth substrate. Moreover, LBAC benefits from the superior lithiophilicity and the porous architecture of BaLi4 skeleton nested in a conductive carbon fiber matrix, leading to stable cycling performance by confining Li stripping/plating in microchannels network of BaLi4 alloy framework and dissipating high current densities. As a result, the LBAC symmetrical cells can run stably for 1,000 h under 1 mA cm-2 and 1 mA h cm-2, and the capacity retention can retain 93.3% after 300 cycles in the full cell with areal capacity of 2.45 mA h cm-2. This work offers a smart designing strategy of 3D Li alloy composite anodes by introducing porous and lithiophilic alloy scaffold as sub-framework of the carbon hosting anode, promising the prospect of Li metal batteries for future applications.