Lithium-Ion Battery Charger Circuit using MCP73831
Lithium Ion Battery Charger Circuit (with Diagrams)
Auto Cut off 3.7 volt Lithium-ion Battery Charger Circuit - Hackster.io
Solar Lipo Charger (3.7V) — Arduino Online Shop
Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger [bq24074] : ID 4755 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits