Portable solar panel for charging
You can use a portable solar panel for charging. They are a source of DC electricity, which provide power to the standard wireless phone charger. There are many solar power phone chargers already available that can be wireless or plugged into the portable panel. The portable solar panel industry has multiple items that have the right output to charge the battery for an iPhone or android.
Wireless charging works using electromagnetic induction. The charger uses an induction coil in the charger to transfer energy to a receiver in the back of the phone to create an alternating electromagnetic field. The receiver coil in the back of the phone converts the electrical field into electricity to charge the battery.
Wireless chargers are available on a small scale. This technology already exists. Soon this wireless charging technology will be available for electric vehicles (trucks and cars) to start using for recharging. A large version of the wireless small charger induction loop is built into the parking place. The same phone charging technology will be in vehicles to enable a car or truck battery to recharge while it is parked in the car space (no contact required).
There are communication devices, drones and medical implants that use proximity recharge coils. Small rechargeable batteries could easily recharge from solar electricity and contactless recharging technology. When the solar panels are not charging the devices can recharge standard lithium batteries so the proximity charger can continue operating after the sunlight goes.