A thick (170 μm) LiFePO4 cathode is fabricated through aerosol jet printing. The printed cathode displays a pattern of aligned high aspect ratio needles which, in cross section, produce micron scale channels. These channels surround regions of LiFePO4 that possess submicron pores. When tested in half cell configuration versus a Li‐foil anode, the specific discharge capacity of the printed cathode is 151 mAh g−1 at a C/15 rate and 105 mAh g−1 at 1C. These values correspond to area normalized discharge capacities of 2.5 and 1.7 mAh cm−2 at current densities of 0.2 and 2.4 mA cm−2, respectively. In a 50 cycle constant current charge/discharge test, the discharge capacity is stable, retaining 89% of its initial C/5 capacity. These results suggest that aerosol jet deposition is a promising printing technique for fabricating high capacity, rate capable, Li‐ion battery cathodes.

Battery research has recently diverged into solid-state chemistry and flexible features to address the increasing demands in electric vehicles and novel electronics. In this study, we successfully fabricate 4-inch sized thin freestanding lithium-ion conducting composite electrolyte membrane. The solid electrolytes are made up of polyethylene oxide (PEO) lithiated with lithium bis(trifluoromethylsulphonyl)imide (LiTFSI) in which submicrometer sized crystalline Li 1.4 Al 0.4 Ge 1.6 (PO 4 ) 3 (LAGP) particles are homogeneously distributed. The impacts of the LAGP loading (20-60 wt%) on the thermal, electrical, and mechanical properties of the composite electrolytes are systematically assessed. The composite membranes exhibit similar conducting behavior of dry polymer electrolytes with two distinct ionic conduction mechanisms transitioned around the melting temperature. The conductivities of the composites are marginally lower than the polymer electrolyte with no LAGP. Addition of LAGP, compared with PEO/LiTFSI, has slightly increased thermal transition temperatures (both glass transition temperature and melting temperature) as well as the crystallinity of PEO. Increasing the amount of LAGP ceramic fillers increased the elastic modulus, reduced the strain to failure point, but has less impacts on the yielding strength. The freestanding ceramic/polymer composite electrolytes with optimal LAGP loading can result appropriate electrical, thermal and mechanical properties and hence, have potential applications to flexible all solid-state lithium-based batteries.

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Lithium aluminium germanium phosphate (LAGP) is attracting a great deal of attention as a solid electrolyte for lithium–oxygen (Li–O2) batteries due to its high ionic conductivity. In this study, LAGP is prepared by a sol–gel process using comparatively low‐cost GeCl2 as one of the reactants. The final product (LAGP) is obtained by sintering the dry precursor gel at 900 °C for 6 h. The influence of the duration of water evaporation during polymerization on the microstructure of LAGP has been examined. The structure, morphology, and electrochemical properties of LAGP are investigated by employing X‐ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption–desorption analysis, and electrochemical impedance spectroscopy. XRD studies confirm the formation of Li1.5Al0.5Ge1.5(PO4)3 as a primary phase along with small amounts of AlPO4 and Li2O as impurity phases. LAGP specimens have ionic conductivities in the range of 10−4 to 10−5 S cm−1 at room temperature. In addition, LAGP also exhibits electrocatalytic activity towards the oxygen‐reduction and evolution reactions. These results demonstrate the potential of LAGP prepared by sol–gel processes as a solid electrolyte for lithium‐ion conduction in solid‐state lithium–oxygen batteries.