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In reversible protonic ceramic cells (RPCCs), due to their fast oxygen reaction kinetics, perovskite-structured cathode materials have been in the spotlight up to this point. However, such materials have some drawbacks such as low phase stability in humid atmospheres, high thermal expansion coefficient, and relatively low proton conductivity despite high electrocatalytic activities when used as steam-air electrodes. Hence, we suggest that novel misfit-layered structure Ca3Co4O9+δ (CCO)-based materials be used to overcome these technical issues with superior performance in RPCCs. Although CCO is a cobaltite-material, CCO has a similar thermal expansion coefficient as BZCYYb electrolyte’s (10‒12×10-6 K-1). Moreover, the plate-like morphology of the CCO-based materials are favorable for the introduction or emission of steam. Further, with alkali metal doping in Ca-site, CCO generates extra charge carrier species with the modified Co oxidation state, which results in high proton uptake and diffusion mechanism. Altogether, 5 mol% potassium-doped CCO-cells show great potential as a cathode material.

Background: Wearable devices for robot-assisted gait training (RAGT) provide overground gait training for the rehabilitation of neurological injuries. We aimed to evaluate the effectiveness and safety of RAGT in patients with a neurologic deficit. Methods: Twenty-eight patients receiving more than ten sessions of overground RAGT using a joint-torque-assisting wearable exoskeletal robot were retrospectively analyzed in this study. Nineteen patients with brain injury, seven patients with spinal cord injury and two patients with peripheral nerve injury were included. Clinical outcomes, such as the Medical Research Council scale for muscle strength, Berg balance scale, functional ambulation category, trunk control tests, and Fugl–Meyer motor assessment of the lower extremities, were recorded before and after RAGT. Parameters for RAGT and adverse events were also recorded. Results: The Medical Research Council scale scores for muscle strength (36.6 to 37.8), Berg balance scale (24.9 to 32.2), and functional ambulation category (1.8 to 2.7) significantly improved after overground RAGT (p < 0.05). The familiarization process was completed within six sessions of RAGT. Only two mild adverse events were reported. Conclusions: Overground RAGT using wearable devices can improve muscle strength, balance, and gait function. It is safe in patients with neurologic injury.