Polymer–Ceramic Composite Cathode with Enhanced Storage Capacity Manufactured by Field-Assisted Sintering and Infiltration

Abstract

Polymer–ceramic all-solid-state Li batteries (ASSLBs) combine the advantages of fully inorganic and polymer-based ASSLBs. In particular, the application of proposed polymer–ceramic composite cathodes could be essential for the enhancement of the energy storage capacity of ASSLBs. The use of a modified field-assisted sintering technique with adjustable pressure and with alternative mica foil enables the fabrication of porous cathodes at a reduced sintering temperature and without side phase formation. This allows sintering of a porous LiCoO2/Li7La3Zr2O12:Ta composite network suitable for polymer infiltration and assembly in an ASSLB from the cathode side. The ceramic LiCoO2/Li7La3Zr2O12:Ta composite cathodes infiltrated with an ion-conducting polymer have shown an enhanced areal storage capacity.

Water-Based Fabrication of a Li|Li7La3Zr2O12|LiFePO4 Solid-State Battery─Toward Green Battery Production

“…The charge capacity drops from 0.36 mAh cm –2 for the first cycle to 0.15 mAh cm –2 for the fifth cycle, while the discharge capacity drops from 0.21 mAh cm –2 for the first cycle to 0.15 mAh cm –2 for the fifth cycle. Such initial cycles with low efficiency and decreasing capacities were also observed in the Li–In|LLZO|LCO SSLBs in our previous studies. ,− Comparing this performance with the high reversibility of the cell comprising the Li metal anode (Figure c), we preliminarily conclude that there is an irreversible reaction in the formation of the Li–In alloy, which leads to the low efficiency and capacity decay in the initial cycles. The cell with a thick C3t cathode exhibits a similar performance in the first five cycles: low efficiency and decreasing capacity.…”

“…The areal capacities are 1.34 and 1.32 mAh cm –2 for 10 and 20 μA cm –2 , respectively, and the specific capacity reaches 131 mAh g –1 , which is lower than the one of thin cathode C3 at 10 μA cm –2 . It seems that some parts of the LFP are not accessible to Li + in the thick cathode (C3t), which is similar to the behavior of thick cathodes with ceramic electrolytes. , When the current density is increased to 50 μA cm –2 , the battery suffers severe degradation. In the third cycle, the battery is normally charged, while the discharge curve shows no more a plateau but a gradual decrease, indicating that the resistance might increase dramatically during discharging.…”

Study of LiCoO2/Li7La3Zr2O12:Ta Interface Degradation in All-Solid-State Lithium Batteries

“…All-solid-state Li batteries (ASSLBs) are a promising solution to overcome the limitations of conventional Li-ion batteries such as low-temperature stability, limited safety, and modest energy storage capacity. − Among the ceramic-based solid electrolytes, ,− the Li 7 La 3 Zr 2 O 12 (LLZO) garnet attracts special attention from researchers and engineers. LLZO exhibits high Li-ion conductivity (increased via substitution by Al and Ta), a broad electrochemical window, and stability against lithium. ,, Significant progress has been achieved in the development and operation of Li batteries with an LLZO electrolyte, a LiCoO 2 (LCO) cathode, and a Li anode. − Nevertheless, the fabrication of reliable LCO|LLZO half-cells remains a challenging task. ,, Moreover, little is known about the properties of the LCO/LLZO interface upon processing and operation, including the development of its microstructure, phase composition, and charge transfer. , …”

Thermal Recovery of the Electrochemically Degraded LiCoO2/Li7La3Zr2O12:Al,Ta Interface in an All-Solid-State Lithium Battery

“…2,5,9,17,21,22 The fabrication of ASSLBs with LCO and LLZO by various processing techniques has been demonstrated in the literature. 2,5,9,17,21,22 However, the cells either suffer from rapid performance degradation or show low storage capacity. 2,5,9,17,21,22 Several groups proposed degradation mechanisms, such as chemical instability during processing, fracture of rigid solid−solid interfaces, or electrochemical decomposition.…”

“…28−31 Advanced sintering techniques, in particular fieldassisted sintering technique also known as spark plasma sintering (FAST/SPS), can also mitigate the secondary phase formation and results in clean interfaces and good electrochemical performance. 5,17 The application of mechanical pressure during FAST/SPS enables the manufacturing of dense components for ASSLBs at reduced temperature and shorter dwell time without formation of secondary phases (Figure S1). 32−34 Once a temperature window ensuring the material stability during sintering is defined, a second degradation mechanism is observed during the electrochemical cycling of cells.…”