Encasing Prelithiated Silicon Species in the Graphite Scaffold: An Enabling Anode Design for the Highly Reversible, Energy-Dense Cell Model

Abstract

Si anodes suffer from poor cycling efficiency because of the pulverization induced by volume expansion, lithium trapping in Li–Si alloys, and unfavorable interfacial side reactions with the electrolyte; the comprehensive consideration of the Si anode design is required for their practical deployment. In this article, we develop a cabbage-inspired graphite scaffold to accommodate the volume expansion of silicon particles in interplanar spacing. With further interfacial modification and prelithiation processing, the Si@G/C anode with an areal capacity of 4.4 mA h cm–2 delivers highly reversible cycling at 0.5 C (Coulombic efficiency of 99.9%) and a mitigated volume expansion of 23%. Furthermore, we scale up the synthetic strategy by producing 10 kg of the Si@G/C composite in the pilot line and pair this anode with a LiNi0.8Co0.1Mn0.1O2 cathode in a 1 A h pouch-type cell. The full-cell prototype realizes a robust cyclability over 500 cycles (88% capacity retention) and an energy density of 301.3 W h kg–1 at 0.5 C. Considering the scalable fabrication protocol, holistic electrode formulation design, and harmony integration of key metrics evaluated both in half-cell and full-cell tests, the reversible cycling of the prelithiated silicon species in the graphite scaffold of the composite could enable feasible use of the composite anode in high-energy density lithium batteries.

Gradient H‐Bonding Binder Enables Stable High‐Areal‐Capacity Si‐Based Anodes in Pouch Cells

“…Furthermore, we compared the lifetime and binder content of pouch cells with Si‐based composite as anodes in recent studies (details refer to Figure 4e). [ 55–60 ] Noticeably, the pouch cell with low‐content PAHT binder exhibits more remarkably cycling performances than those of previous reports. As demonstrated above, the PAHT binder contributes to improving the electrochemical properties of both Si and Si‐C anodes, showing a tremendous potential towards practical application.…”

“…e) Comparison of the lifespans and binder contents of the pouch cells reported in the literature. [ 55–60 ] The battery in this work shows an outstanding cycliability at a low binder content of 4.2 wt%. f) Cycling performance of the NCM/Si‐C full pouch cell at 1C between 2.75 and 4.2 V.…”

Challenges and Recent Progress on Silicon‐Based Anode Materials for Next‐Generation Lithium‐Ion Batteries

“…However, the energy density is below expectations to develop more cost‐effective Si/graphite anode. The preparation process of Si/graphite anode greatly affects the properties, there are five main synthetic methods, including CVD, [ 89 ] ball milling, [85b] spray drying, [86b] thermochemical pyrolysis, [85a] and liquid solidification [7b] . The various synthetic methods influence the distribution of Si in anode which determined to the electrode swelling.…”

“…The cabbage‐inspired graphite scaffold to accommodate the volume expansion of silicon particles in interplanar spacing (Si@G/C) has been synthesized by multistep reaction, including sand milling, spray drying, and CVD. [ 89 ] First, the micrometer‐sized silicon ( D 50 ≈4–8 μm) was converted to nanoscale (≈100 nm) by the sand milling process (process I). After sand milling process, the cross‐linked poly (acrylamide‐ co ‐diallyldimethylammonium chloride) PDDA was grafted on the surface of Si nanoparticles (PDDA‐Si) to prevent spontaneous agglomeration of Si nanoparticles.…”

Commercialization‐Driven Electrodes Design for Lithium Batteries: Basic Guidance, Opportunities, and Perspectives

“…The prelithiation technique has been tried to apply in practical applications to increase the initial Coulombic efficiency, stabilize SEI formation, and enhance cycling stability of both anodes and cathodes, especially for the high-capacity electrode materials with a low initial Coulombic efficiency. [226][227][228] However, the prelithiation technique raises high demands on the environmental conditions, low humidity and oxygen content. Meanwhile, overlithiation causes the Li nucleation and accommodation on the top surface of the electrode, thus, the prelithiation depth should be controlled precisely.…”