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

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.