Topology Optimized Prelithiated SiO Anode Materials for Lithium‐Ion Batteries

Abstract

Silicon monoxide (SiO)‐based materials have great potential as high‐capacity anode materials for lithium‐ion batteries. However, they suffer from a low initial coulombic efficiency (ICE) and poor cycle stability, which prevent their successful implementation into commercial lithium‐ion batteries. Despite considerable efforts in recent decades, their low ICE and poor cycle stability cannot be resolved at the same time. Here, it is demonstrated that the topological optimization of the prelithiated SiO materials is highly effective in improving both ICE and capacity retention. Laser‐assisted atom probe tomography combined with thermogravimetry and differential scanning calorimetry reveals that two exothermic reactions related to microstructural evolution are key in optimizing the domain size of the Si active phase and Li2SiO3 buffer phase, and their topological arrangements in prelithiated SiO materials. The optimized prelithiated SiO, heat‐treated at 650 °C, shows higher capacity retention of 73.4% and lower thickness changes of 68% after 300 cycles than those treated at other temperatures, with high ICE of ≈90% and reversible capacity of 1164 mAh g−1. Such excellent electrochemical properties of the prelithiated SiO electrode originate from its optimized topological arrangement of active Si phase and Li2SiO3 inactive buffer phase.

Endothermic Dehydrogenation-Driven Preventive Magnesiation of SiO for High-Performance Lithium Storage Materials

“…For the electrochemical tests, electrodes of SiO, C-SiO, and Si/Mg 2 SiO 4 nanocomposite materials were prepared and coin-type half-cells (CR2032, Wellcos Co., Korea) were assembled. The detailed procedure can be found in our previous work . Galvanostatic charge (Li + insertion) measurements were performed using constant current–constant voltage (CC-CV) mode within the voltage range of 0.01–1.5 V ( vs Li/Li + ) at 50 mA g –1 of current density for initial two cycles, followed by 300 cycles at 500 mA g –1 .…”

“…The detailed procedure can be found in our previous work. 38 Galvanostatic charge (Li + insertion) measurements were performed using constant current−constant voltage (CC-CV) mode within the voltage range of 0.01−1.5 V (vs Li/Li + ) at 50 mA g −1 of current density for initial two cycles, followed by 300 cycles at 500 mA g −1 . The operating voltage of CV mode was 10 mV (vs Li/ Li + ) up to 10 mA g −1 .…”

Is Soft Carbon a More Suitable Match for SiOx in Li‐Ion Battery Anodes?

“…[8] Despite this, a nonnegligible volume change effect remains the main limitation that prevents SiO x to replace conventional Gr anodes. [9] "Trapping effect" is prevalent in Si-based anodes. [10] Previous reports have mainly attributed this phenomenon to the limited electronic and ionic conductivity of Si-based materials, which inhibits the dealloying of Si-alloyed Li and thereby worsen the capacity performance.…”

“…[ 8 ] Despite this, a nonnegligible volume change effect remains the main limitation that prevents SiO x to replace conventional Gr anodes. [ 9 ]…”

Unleashing the Potential of High-Capacity Anodes through an Interfacial Prelithiation Strategy

“…With the rapid market penetration of electric vehicles, high-end electronics, and distributed power solutions worldwide, a further boost of the energy density metrics in lithium-ion batteries (LIBs) with the balanced power output and operational safety becomes more urgent than ever. − Featuring a high-capacity lithiation capability (3579 mAh g –1 in terms of Li 15 Si 4 ), environmental benignity, and appropriate equilibrium potential (<0.4 V vs Li/Li + ), silicon (Si)-based materials have been considered as the most promising alternative to the commercial graphite anodes. ,− Unfortunately, these favorable attributes are offset by mechanical fatigue and electrode pulverization, which are induced by the ∼300% volume expansion upon the lithiation process. − In addition, the Li–Si alloy intermediates react with the commercial carbonate electrolyte at low equilibrium voltages, thereby leading to the accumulation of the interfacial impedance as well as the electrical insulation of the active ingredient. , The repetitive buildup of the fragile solid-electrolyte interphase (SEI) layer, along with the retarded kinetics of the Li–Si dealloying, irreversibly traps the active Li + and thus continuously leads to cation depletion under lean electrolyte conditions (<3.0 g Ah –1 for the commerical 18650 batteries or even less than 1.5 g Ah –1 for the pouch-format prototypes), − let alone the unexplored cross-talk effect of the transitional metal migration from the layered oxide cathode to the anode surface, especially at the extreme operation scenarios. Despite the tremendous research endeavors toward hybrid composite designs, electrode architecture innovation, or artificial protection strategies (ceramics, polymer, or composite coating), − the performance progress is still limited to half-cell evaluations or low-areal-capacity loading of Si electrodes (<3 mAh cm –2 ), the insufficient cation utilization degree of which thus remains as the bottleneck issue for energy-dense battery prototyping. − …”