Solar powered pathway lights should be used with caution. They don't last very long so the sustainable aspect of the light is low. Try to find similar light alternatives that can be hard wired and use a solar collector.
Top 28 Ideas Adding DIY Backyard Lighting for Summer Nights
DIY glow in the dark stepping stones. Line a pathway with rocks painted in glow in the dark paint. During the day they “charge” in the sun and in the evening they reflect the stored light. Rust-Oleum Glow in the Dark Brush-on Paint.