Quasi-Solid-State Li–O₂ Batteries Performance Enhancement Using an Integrated Composite Polymer-Based Architecture

Abstract

Heightened attention for solid-state Li–O2 batteries (SSLOBs) exists due to their improved safety, wider electrochemical window, and high energy density in addition to the solid electrolyte’s innate capability of suppressing Li dendrite penetration and shielding the Li metal anode from oxygen, CO2, and moisture in the air, in comparison with the conventional Li–O2 batteries using liquid organic electrolytes. Herein, a cathode supported quasi-SSLOB with an integrated composite polymer-based architecture (ICPA) is developed with reduced interfacial resistance, extended triple-phase boundaries (TPBs) for Li–O2 reactions, and a thin film solid-state electrolyte. The Li–O2 cell with ICPA (denoted as ICPA cell) exhibits a lower charge transfer impedance than its counterpart with the same composite polymer electrolyte (CPE) but a nonintegrated structure (termed the CPE cell). The former shows reduced interfacial impedance between electrolyte and cathode and increased TPBs. Furthermore, the ICPA cell delivers higher discharge capacity, lesser capacity decay, and significantly lower impedance rise after cycles than the CPE cell, ascribed to the continuous Li-ion transport in ICPA and the resulting more efficient discharge and charge processes. Under a limited capacity cycling protocol of 300 mAh g–1, the ICPA cell achieves excellent reversibility for 78 cycles, remarkably surpassing the CPE cell which only performs 44 cycles in addition to showing half of the after-cycle impedance compared to that for the CPE cell. Nonetheless, the same composite polymer electrolyte used for both CPE- and ICPA-based cells demonstrates excellent stability toward Li metal after long-term cycling. These findings manifest that the design and application of cathode supported SSLOB with ICPA can be a promising approach to achieve high-performance Li–O2 batteries.

Enhancing the Performance of Lithium–Oxygen Batteries with Quasi-Solid Polymer Electrolytes

“…The Li|QSE 2 |O 2 has the longest cycle life, while the life of Li|QSE 3 |O 2 is the shortest. The lives of LOBs increase first and then decrease with the reduction of TEGDME ratio in the electrolyte, which may have been affected by the number of triple-phase boundaries (TPBs) for the reaction of Li + , electrons, and O 2 . – Compared LE with QSEs, the TPBs should increase with the decrease of TEGDME content because the less liquid exponent, the more chance electrode material is exposed to oxygen. Therefore, the cycle lives of batteries increase with the reduction of TEGDME in the electrolyte first.…”

Constructing Rechargeable Solid‐State Lithium‐Oxygen Batteries

“…Moreover, Song et al developed a cathode supported QSE with an integrated composite polymer-based architecture (ICPA). [115] The integrated structure is constructed by CSE with PEO, lithium salt and LLZO cast on the composite cathode. Compared with the common cathode, it shows lower charge transfer impedance.…”

Fundamental Understanding and Construction of Solid‐State Li−Air Batteries

“…During charge, Li 2 O 2 is initially decomposed which is followed by the removal of the by‐products of Li 2 CO 3 and LiOH. Therefore, one discharge plateau representing the generation of the discharge products of Li 2 O 2 and two charge platforms referring to the initial Li 2 O 2 decomposition and the subsequent removal of Li 2 CO 3 and LiOH are generally included in solid‐state Li–air battery [4b,46] . Therefore, to achieve favorable, practical high‐performance solid‐state Li–air batteries, the following key issues referring to air cathode, Li anode, solid electrolyte as well as the regulation of electrolyte/electrode interfaces should be well considered during the design and construction of the battery: 1) Battery component optimization.…”

“…In view of the abovementioned challenges, replacing the aprotic liquid electrolyte with solid electrolyte would provide a promising strategy. [ 4 ] Solid electrolyte with superior safety, mechanical strength and chemical/electrochemical stability, wide electrochemical window, low‐cost processing, which is favorable to avoiding the electrolyte volatilization and thus sustaining the integrity of the triple‐phase interface, keeping the batteries from combustion or explosion, stopping Li dendrites from penetrating the separator, protecting Li anode from corrosion caused by the harmful reactions between the components from open‐air atmosphere and active Li metal, eliminating the electrolyte decomposition originated from the attack of strong nucleophilic intermediates. [ 5 ] All these superiorities would greatly guarantee the safety and long cycling stability of Li−air batteries.…”