Dry-air-stable lithium silicide–lithium oxide core–shell nanoparticles as high-capacity prelithiation reagents

Abstract

Rapid progress has been made in realizing battery electrode materials with high capacity and long-term cyclability in the past decade. However, low first-cycle Coulombic efficiency as a result of the formation of a solid electrolyte interphase and Li trapping at the anodes, remains unresolved. Here we report Li x Si-Li 2 O core-shell nanoparticles as an excellent prelithiation reagent with high specific capacity to compensate the first-cycle capacity loss. These nanoparticles are produced via a one-step thermal alloying process. Li x Si-Li 2 O core-shell nanoparticles are processible in a slurry and exhibit high capacity under dry-air conditions with the protection of a Li 2 O passivation shell, indicating that these nanoparticles are potentially compatible with industrial battery fabrication processes. Both Si and graphite anodes are successfully prelithiated with these nanoparticles to achieve high first-cycle Coulombic efficiencies of 94% to 4100%. The Li x Si-Li 2 O core-shell nanoparticles enable the practical implementation of high-performance electrode materials in lithium-ion batteries.

Challenges and Recent Progress in the Development of Si Anodes for Lithium‐Ion Battery

“…[54] Compared with microscale stabilized lithium metal powder, Li x Si nanoparticles show multiple excellent properties: First, nanoscale Li x Si particles with size around 100-200 nm can distribute homogeneously in the entire electrode structure for a uniform and fast prelithiation. Second, the surface of Li x Si nanoparticle can be modified to realize ambient air compatibility.…”

“…[52,53] The third one is to apply Li x Si nanoparticles from chemically synthesis as a potential prelithiation reagent. [54] We will discuss the three main methods one by one.…”

“…d) Reproduced with permission. [54] Copyright 2014, Nature Publishing Group. sponsor spontaneous prelithiation for SEI formation, because of an external short circuit built between lithium metal foil and c-SiO x electrode.…”

“…The three main approaches of prelithiation can prestore Li and realize initial Coulombic efficiency of 90% (Li metal powder), [55] 94.9% (electrochemical prelithiation), [50] >100% (Si/polymer/lithium), [56] and >100% (Li x Si nanoparticles). [54] In summary, the main three methods indeed improve the initial Coulombic efficiency of silicon anode. Through structure design and sacrificial lithium, the initial Coulombic efficiency can reach or exceed the commercial level of state-of-the-art graphite anodes (90%) step by step.…”

Pre-Lithiation Strategies for Rechargeable Energy Storage Technologies: Concepts, Promises and Challenges

“…Zhao et al [32] introduced the use of dry-air-stable lithium silicide-lithium oxide core-shell nanoparticles (Li x Si-Li 2 O) for the pre-lithiation of Si and graphite electrodes, achieving high first cycle Coulombic efficiencies of 94% to >100%, in Li metal cells. The Li x Si-Li 2 O nanoparticles (NPs) were prepared by mechanical mixing Si NPs and Li metal foil (melting point: ≈180 • C) at 200 • C for 6 h in an argon filled glove box.…”