Spontaneous and mass-conserved formation of continuous Si frameworks

TL;DR

This paper introduces a novel electrochemical method to spontaneously form continuous, sub-2 nm silicon frameworks with tunable pores through controlled phase transformations, avoiding material loss and expanding applications in nanotechnology.

Contribution

It presents a new approach for silicon framework formation via single electrochemical dealloying, leveraging phase transformation dynamics at room temperature.

Findings

Silicon frameworks form spontaneously without gravimetric loss.

Transformations produce uniform sub-2 nm spherical silicon structures.

Pore sizes are tunable through process control.

Abstract

Controlled formation of porous silicon has been of primary importance for numerous landmark applications such as light emitting sources, sensors, actuators, drug delivery systems, and energy storage applications. Frequently explored methods to form the structures have long relied on selective etching of silicon, which still stands as the most controllable and reliable methods to highlight essence of the applications. Here, we demonstrate an unprecedented approach to form silicon framework, which is spontaneously formed with atomistic arrangement of silicon without gravimetric loss via single electrochemical (de)alloying with lithium. Carefully controlling bare crystallinity of Si and composite/electrode designs, we reveal that the key prerequisite to forming the structure lies in using unique dealloying dynamics of crystalline-amorphous phase transformations at room temperature. Using the feature, we clearly highlight that commercially available nano-structured silicon particles can abruptly yet uniformly transform into continuous sub-2 nm spherical silicon frameworks with size-tunable pores.