Elimination of “Voltage Noise” of Poly (Ethylene Oxide)-Based Solid Electrolytes in High-Voltage Lithium Batteries: Linear versus Network Polymers

Abstract

HIGHLIGHTS PEO-based solid polymer electrolytes (SPEs) are stable up to 4.6 V versus Li|Li + But, linear PEO-based SPE results in a ''voltage noisefailure'' in NMCkLi cells Failure disappears when PEO is incorporated in a semi-interpenetrating network Charge/discharge cycling possible even at 40 C in NMC622kLi cells

Effective Optimization of High Voltage Solid‐State Lithium Batteries by Using Poly(ethylene oxide)‐Based Polymer Electrolyte with Semi‐Interpenetrating Network

“…s-IPN can be regarded as trapped PEO chains in a network obtained via polymerization of a network former based on poly(ethylene glycol)dimethacrylate (PEGdMA). [21] The formation of the s-IPN is confirmed via the gelation test. The use of a linear PEO-based SPE results in a failure visible by the random appearance of voltage noise (exemplary profile), [16] while the cell with s-IPN PEO-based SPE operates failure-free.…”

“…The membrane was polymerized under N 2 flux at 80 °C for 1 h and dried over night at 80 °C under reduced pressure (10 −3 mbar). [21] The concentration of PEGdMA was referred to the PEO content. The Li salt amount was adjusted to the MW of the used PEGdMA.…”

“…[20] A solution for overcoming this failure is the integration of the linear, rather soft PEO-based SPE, into a more mechanically robust semi interpenetrating network (s-IPN) (Scheme 1). [21] Still mainly consisting of PEO units, the s-IPN PEO-based SPE can suppress the Li dendrite penetration by improved mechanical rigidness and realize a voltage-noise-free charge/discharge cycling (Figure 1). [21] The rigid structure of the s-IPN PEO-based SPE restricts the polymer chain mobility, thus decreases the ionic conductivity compared to the linear PEO-based SPE.…”

“…[21] Still mainly consisting of PEO units, the s-IPN PEO-based SPE can suppress the Li dendrite penetration by improved mechanical rigidness and realize a voltage-noise-free charge/discharge cycling (Figure 1). [21] The rigid structure of the s-IPN PEO-based SPE restricts the polymer chain mobility, thus decreases the ionic conductivity compared to the linear PEO-based SPE. [21] One strategy to increase ionic conductivity is commonly an increased Li salt concentration.…”

“…[ 21 ] Still mainly consisting of PEO units, the s‐IPN PEO‐based SPE can suppress the Li dendrite penetration by improved mechanical rigidness and realize a voltage‐noise‐free charge/discharge cycling ( Figure ). [ 21 ]…”