You describe a difficult situation that I have been in fairly recently. I'm not going to claim that I handled it brilliantly, but I am going to tell you what I would do, if I found myself in the same position again.
Turn it around, ask them what you're not doing that they'd like you to be doing. If it is a technical job then ask them if they'd like you to free up the time for them to do it themselves. If it's things like code-reviews, that they don't feel qualified for, then offer to teach them.
More likely they won't have a clue what they want you to do. They just know that they have no idea what you're actually doing. If that's the case, you're doing your job well, and you should explain that to them. They shouldn't see ANY of the politics you have to deal with day-to-day. It's depressing and they don't need it.
Also remind them that you have a boss and it's up to them to judge your performance as a team lead. They do know what you're doing all day and if they don't then that's their failing, not yours.
But qualify that somewhat. They need to know that you're working in their interests. With backing from your boss, offer them a part of your role. Say that they can take responsibility for one project or task in particular, and you will back them up. Let them see a portion of the garbage you're protecting them from.
All that said, you do need to keep your hand in, technically speaking. You don't need to be as technical as they do, but you do have to be on top of the latest technologies and what they offer.
If we're honest, management is a role with peaks and troughs of effort. When you're needed, you're needed immediately, but there are times when you do stop. Use those times to solve technical problems that your team can never find the time to solve. Get into the CI server and see what you can do to improve it. Have a look at a framework that the team has been saying would be useful and see how hard it would be to migrate. That sort of thing.
But don't ever become a bottleneck. Never become the guy someone is relying on for a key delivery. Cause you can guarantee that you'll end up with a political situation to deal with at just the wrong moment.
Finally, and this is the biggest lesson I've learned, do not pander to one or two negative influences within the team. Never forget that you're their boss for a reason.