Your "Diamond Shaped" key fob has a rechargeable battery and your ignition switch should charge that battery for you. To do this put the key fob into the ignition and turn it to position 2 or 3

A full charge takes 24 to 30 hours to complete depending on how healthy your battery is

Battery health degrades over time. If you follow above procedure and it does not charge the fob then it is most probably a dead battery

One trick you could try is using a stronger QI charger. They type used to charge mobile phones. Of course you will need to monitor your key for signs of overheating. Try a short charging session of one hour - with close observation - and see if it will resurrect the battery

If nothing works I would get a VL2020 battery off Amazon/eBay and replace it myself. It is trivial and shouldn't take more than 10 minutes

Please do not use non-rechargeable batteries to fix the key

Good luck