Amazon.com: DC 3.7V 2100mAh 804050 li-ion Lithium Ion Polymer Battery Replacement for DIY 3.7-5V Electronic Product, Mobile Energy Storage Power Supply : Electronics
Make a 3.7 V Li – ion Battery Charger using TP-4056 (Part 9/9)
Multi-cell Charger | 1-4a Multi-cell | Li-ion Charger | Boost Charger | Dc Dc Charger - 1-4a - Aliexpress
Amazon.com: Taidacent 10 Pcs 3.7V to 9V 5V 2A Voltage Adjustable Step Up 18650 Lithium Battery Charging Boost Discharge Integrated Module : Electronics
Amazon.com: 5Pcs 2A USB 18650 Lithium Li-ion Battery Charger Module Boost 3.7V to 5V 9V 12V : Electronics
Single Universal 3.7 V Li-Ion Battery Charger - Electrothinks: Explore, Learn, Innovate
Does it have any problems to charge a lithium ion 3.7 standard battery with 5V USB voltage? - Quora
BU-409: Charging Lithium-ion - Battery University
Auto Cut off 3.7 volt Lithium-ion Battery Charger Circuit - Hackster.io