Understanding the lithiation/delithiation mechanism of Si_1−xGe_x alloys

Abstract

GexSi1−x alloys have demonstrated synergetic effects as lithium-ion battery (LIB) anodes because silicon brings its high lithium storage capacity and germanium its better electronic and Li ion conductivity.

Cobalt Carbodiimide as Negative Electrode for Li‐Ion Batteries: Electrochemical Mechanism and Performance

“…Full delithiation was enforced by holding the potential at 3 V at the end of charge. The whole data set consisting of 126 Co K‐edge XAS spectra was treated globally using the chemometric approach already described in our previous studies . In short, the number of independent components needed to describe the whole set of spectra is first obtained by PCA, and in a second step the corresponding pure spectral components are reconstructed by MCR‐ALS algorithm by imposing physical and chemical constraints .…”

Si and Ge‐Based Anode Materials for Li‐, Na‐, and K‐Ion Batteries: A Perspective from Structure to Electrochemical Mechanism

“…Both Si and Ge remain as a solid solution during the cycling, with the presence of at least two different amorphous lithiated intermediates. This solid solution leaves a fingerprint that impacts the size and the arrangement of the formed lithiated phases at the end of discharge, the so‐called “memory effect.” This leads to an optimized interface between the lithiated nanograins, which allows a reconstruction of the Si 1− x Ge x phase instead of Si+Ge upon charge …”

Best Performing SiGe/Si Core‐Shell Nanoparticles Synthesized in One Step for High Capacity Anodes

“…This evolution might originate, at least partially, from the sequential lithiation of the different Si 100‐ x Ge x phases depending on the Ge content. Indeed, as Ge and Si have distinct lithiation potential E vs. Li + /Li (respectively close to 380 mV and 250 mV), Ge‐rich phases are expected to lithiate first. Another possible mechanism leading to Bragg peak displacement could be the increasing compressive stress applied to the core of the nanoparticles by the lithiation front trapped between the pristine core and the outer lithiated layer, as already observed in pure Si nanoparticles .…”