Absolutely, mate! You can store your backup keys on a mobile device. Most bitcoin wallet apps will let you write down a "recovery seed" when you first set up the wallet. This is usually a list of 12 or 24 words.

You can keep this word list safe as your backup. If anything happens to your phone, you can use the recovery seed to restore your wallet and access your bitcoins on any other device.

But remember: these words are super important! If anyone else gets them, they can steal all yer coins. And if ya lose 'em... well, better not lose 'em.