A Silica‐Aerogel‐Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus

Abstract

High-energy all-solid-state lithium (Li) batteries have great potential as next-generation energy storage devices. Among all choices of electrolytes, polymer-based systems have attracted wide-spread attention due to their low density, low cost, and excellent processability. However, they are generally mechanically too weak to effectively suppress Li dendrites and have lower ionic conductivity for reasonable kinetics at ambient temperature.Herein, an ultra-strong reinforced composite polymer electrolyte (CPE) has been successfully designed and fabricated by introducing a stiff mesoporous SiO 2 aerogel as the backbone for a polymer-based electrolyte. The interconnected SiO 2 aerogel not only perform as a strong backbone strengthening the whole composite, but also offer large and continuous surfaces for strong anion adsorption, which produces a highly-conductive pathway across the composite.As a consequence, a high modulus of ~0.43 GPa and high ionic conductivity of ~0.6 mS cm -1

MXene‐Based Mesoporous Nanosheets Toward Superior Lithium Ion Conductors

“…To further evaluate the electrochemical stability of the MXene‐mSiO 2 containing electrolyte, lithium symmetric cells with the electrolytes were assembled and tested at room temperature. Remarkably, an ultralong and stable stripping/plating cycling up to 2000 h is achieved for the MXene‐mSiO 2 containing electrolyte at 0.05 mA cm −2 , superior to the reported SiO 2 /PEO electrolyte (≈450 h) . Moreover, the initial overpotential is only 19.2 mV, much lower than that of pure ePPO electrolyte (155.9 mV) and mSiO 2 containing electrolyte (44.7 mV) in Figure 4 a .…”

“…Remarkably, an ultralong and stable stripping/plating cycling up to 2000 h is achieved for the MXene‐mSiO 2 containing electrolyte at 0.05 mA cm −2 , superior to the reported SiO 2 /PEO electrolyte (≈450 h) . Moreover, the initial overpotential is only 19.2 mV, much lower than that of pure ePPO electrolyte (155.9 mV) and mSiO 2 containing electrolyte (44.7 mV) in Figure 4 a . Even after cycling for 2000 h, the overpotential is still kept at 39.6 mV, originating from high ionic conductivity of MXene‐mSiO 2 containing electrolyte.…”

“…In contrast, the pure ePPO electrolyte and mSiO 2 containing electrolyte rapidly failed after cycling for hundreds of hours. More importantly, after cycling up to 2000 h, the intrinsic and concentration overpotentials are only 13.5 and 26.1 mV (Figure S19, Supporting Information), respectively, much lower than those of the reported SiO 2 /PEO electrolyte (25 and 52 mV) at the same current rate . The lithium symmetric cell can still operate up to 500 h with low overpotentials (70 mV) at 0.2 mA cm −2 (Figure b).…”

Li+‐Containing, Continuous Silica Nanofibers for High Li+ Conductivity in Composite Polymer Electrolyte

“…Among the various types of SSEs, polymer solid electrolytes with excellent flexibility and processability have attracted much interests, while their poor ionic conductivity and mechanical strength impede the further applications . Composite polymer electrolytes (CPEs) composed of polymer electrolytes and inorganic fillers, which can provide significantly enhanced ionic conductivity and mechanical properties, have gained increasing attention over years . Polyethylene oxide (PEO)‐based composite electrolyte is one of the most investigated CPEs since its birth .…”

“…Composite polymer electrolytes (CPEs) composed of polymer electrolytes and inorganic fillers, which can provide significantly enhanced ionic conductivity and mechanical properties, have gained increasing attention over years . Polyethylene oxide (PEO)‐based composite electrolyte is one of the most investigated CPEs since its birth . Generally, inorganic fillers (active Li + conductors or passive non‐Li + conductors) are introduced into the PEO‐based polymer matrix to change its crystallization kinetics, creating local amorphous regions at the filler/polymer interfaces for efficient Li + conduction .…”