Rational design of PANI-modified three-dimensional dendritic hierarchical porous Cu-Sn nanocomposites as thick anodes with ultrahigh areal capacity and good cycling stability

Abstract

A simple and effective one-step strategy gives freestanding 3D dendritic hierarchical porous (DHP) Cu-Sn nanocomposites by chemically dealloying a designed Cu35Sn65 (at.%) alloy with dendritic segregation in a specific corrosive solution. A 3D DHP Cu-Sn modified by polyaniline (PANI) further makes the nanocomposites with improved conductivity and structural stability, which are typical of bimodal pore-size distribution comprising a dendritic micron-sized ligament-channel structure with interconnected nanoporous channel walls. The as-prepared 12h dealloyed 3D DHP nanocomposites with ca. 200 mu m in thickness can serve as binder-free thick anodes for lithium-ion batteries (LIBs) and exhibit enhanced Li storage performance with a ultrahigh first reversible capacity of 13.9 mAh cm(-2) and an initial CE of 85.8%, good cycling stability with a capacity retention of 73.5% after 50 cycles, and superior rate capability with a reversible capacity of 11.95 mAh cm(-2) after high-rate cycling. These Sn-based anodes can effectively alleviate the volume variation, enhance the loading of active materials, strengthen the stability of solid electrolyte interphase films, shorten the Li+ migration distance, and improve the electron conductivity. Additionally, the Sn content and areal capacity of the 3D DHP electrode can be tuned by changing the dealloying time of the initial alloy for 3D tin-based thick anodes with adjustable capacities toward high-performance LIBs.