Yes.
VOLTRA I can be charged with a portable charger that supports USB Power Delivery (PD) protocol, such as popular brands like Anker. Suggested specifications are as follows:
Output Port: USB-C output
Charging Protocol: USB PD
Output Power: Minimum 22.5W, 30W or higher recommended
Output Voltage Range: Supports 9V / 12V / 15V / 20V
Recommended Capacity: 10,000mAh to 20,000mAh