Improved High Rate and Temperature Stability Using an Anisotropically Aligned Pillar-Type Solid Electrolyte Interphase for Lithium-Ion Batteries

Honeycomb-like 3D ordered macroporous SiOx/C nanoarchitectures with carbon coating for high-performance lithium storage

SiOx anodes are garnering significant interest in lithium-ion batteries (LIBs) due to theirs low voltage plateau and high capacity. However, critical drawbacks, including high expansion rate and low electronic conductivity, severely limit their practical applications. While 0D, 1D, and 2D scale nanostructures have been proven to mitigate these issues, these materials tend to accumulate after prolonged cycling, leading to adverse effects on the mass transfer processes within the electrode. Herein, we have developed a honeycomb-like SiOx/C nanoarchitecture with carbon coating based on a 3D ordered macroporous (3DOM) structure. The 3D interconnected pore windows facilitate the diffusion and transport of lithium ions (Li+) in the electrolyte, and the extremely thin walls (<15 nm) provide a shorter transport path for Li+ in the solid. The carbon cladding buffers volume expansion and enhances electronic conductivity. The as-prepared anode demonstrates a high reversible capacity of 1068 mAh/g and an initial coulombic efficiency of 70.7 %. It maintains a capacity of 644 mAh/g (capacity retention of 84.63 %) even at a high current of 1.0 A/g after 700 cycles. The unique honeycomb-like structure offers enormous insights into the study of energy storage in 3D materials.

Constructing Densely Compacted Graphite/Si/SiO2 Ternary Composite Anodes for High-Performance Li-Ion Batteries

Graphite has dominated the market of anode materials for lithium-ion batteries in applications such as consumer electronic devices and electric vehicles. As commercial graphite anodes are approaching their theoretical capacity, significant efforts have been dedicated towards higher capacity by blending capacity-enhancing additives (e.g., Si) with graphite particles. In spite of the improved gravimetric capacity, the areal capacity of such composite anodes might decrease due to excess void spaces and an incompatible material size distribution. Herein, a rational design of compact graphite/Si/SiO₂ ternary composites has been proposed to address the abovementioned issues. Si/SiO₂ clusters with an optimal particle size are homogeneously dispersed in the interstitial spaces between graphite particles to promote the packing density, leading to a higher areal capacity than that of pure graphite with equivalent mass loading or electrode thickness. By taking the full intrinsic advantages of graphite, Si, and SiO₂, the composite electrodes exhibit 553.6 mAh g^-1 after 700 cycles with a capacity retention of 95.2%. Furthermore, the graphite/Si/SiO₂ electrodes demonstrate a high coulombic efficiency with an average of 99.68% from 2nd to 200th cycles and areal capacities above 1.75 mAh cm^-2 during 200 cycles with an areal mass loading as high as 4.04 mg cm^-2. A packing model has been proposed and verified by experimental investigation as a design principle of densely compacted anodes. The effective strategy of introducing Si/SiO₂ clusters into the void spaces between graphite particles provides an alternative solution for implementation of graphite-Si composite anodes in next-generation Li-ion cells.