Does iphone have external hard disk for storage?

Same as topic because i dont want to save file inside my iphone via icloud everytime and icloud needs through wifi ,so i cant directly download from icloud to iphone conveniently.
If there is external hard disk or usb-size storage for iphone ,i can free my iphone space and download everytime and everywhere when i want to use again directly

http://store.apple.com/hk-zh/product/HF8F2/mophie-space-pack-battery-case-with-32gb-storage-for-iphone-5s

mophie space pack Battery Case with 32GB Storage for iPhone 5s

好贵