Good question, oldyuk. But I think the ZPower recharging system has some advantages too. Users can switch between the rechargeable batteries and regular batteries if there is no electrical outlet available for charging. As far as I know, if you have lithium-ion batteries and you have no electricity, you are stuck with hearing aids that won’t work if their charge goes dead. That is, unless you carry an extra power source, which some HA manufacturers make available.
Lithium-ion batteries may have more power and last longer–but you also have to take them into your audiologist when the batteries need replacing. I think that means that the audiologist has to send the HAs to the manufacturer to change the batteries, because the cases are sealed and the audiologists cannot open them in the office. So, if you wear lithium-ion powered HAs, you will most likely be without them for a few days when the batteries need changing. Hopefully, your audiologist will be able to provide you with loaner HAs during that time.
With ZPower, you can always switch to regular batteries while the audiologist orders new rechargeable ones for you. So you are never without your own HAs during the battery replacement process. It’s a trade off, I guess–and everyone has their own personal preferences. But, i do think that lithium-ion is probably where most HA manufacturers are going to go in the future. That is, if they don’t come up with something better in the meantime. Personally, I’ve wondered about the safety of lithium-ion batteries in HAs as well. I don’t think they know the long-term health risks that might be involved. Not to mention that some lithium-ion powered cell phones have spontaneously erupted into flames. This is a controversial topic, but it does make one ponder…