So I recently bought volibear and was wondering what builds are suggested for him. Is going full tank the way to go? or are there different types of builds that he works well with?

Get some AS too. Ionic Spark gives him everything he wants: AD, AS, HP, and makes him look cool.

I've built wits end on him a few times, it seemed to be an ok item.
Ionic Spark on the other hand, is mainly just a joke item in my opinion, so I won't be building that on him.

A joke item? lol. It synergizes with his whole kit and you should build it all the time.

Other good items for him are Aegis, Omen, Frozen Mallet (Atma's). Wit's End is a good option if the enemy team has a lot of %HP damage but you really want to be getting as much HP as possible otherwise.

Any tips for Voli? I really want to make him work, but outside a few memorable moments he seemed pretty lack luster. I just feel like he wants to many things.

Atkspd, CDR, Health, atk damage, armpen, resistances, sustain. The sustain is what really gets me. He's one of the few tanky champs I play that I just feel like I'm getting worn down over the course of a fighting and can do nothing about it(other than when his ult is up). Maybe it's because I keep getting sent bot with him.

I did enjoy the time I got Ionic Spark though. It fits stats wise and thematically.

*edit*
And by "ult" I meant passive.

Yeah, he's just too hard to build for. Zeke's made it a lot easier to get CDR on him though. You could go CDR boots + Zeke's + masteries or Omen + Visage + Zeke's if you need to get Mercs (doesn't leave much room for anything else though).

He's considered low tier on SR as well so it's safe to say he was overnerfed in the damage department. The best thing to do is to max CDR, get mallet and be disruptive, gank a lot etc.

I myself am well aware and apparently so is everyone else, that voli is a sub par champ. This doesn't really matter to me since his kit is fun, and he can be as others have already said, disruptive. Normally I go mercs to help him be a little more tankier, but I was forced to try out cdr boots since I had the cursor bug, and could only manage to buy recommended items.

The cdr deffinitely helps him out a bunch, and zekes seems like a decent item to build on him.

Do you think items like aeigis, tri force or other crit items would be useful on him?

He's not too hard to build for if played as a bruiser/flanker. I think people try to play him as a tank and it doesn't work out so well (charge head on for disaster). My usual build was prospectors blade -> CDR boots -> phage -> sv -> fratmas -> situational (wit's/ionic/sanguine). Tank/AS/MS runes/masteries.

He's a strong ganker too, a good way to get vengeance on those pesky urgots.

Mercs, Mallet, Wit's End, and Frozen Heart was my build when I played him. If the game wasn't over by then, Ionic Spark and Atma's Impaler.

Come to think of it, that build could probably have been improved with Ionian, SV, Ionic Spark, Atma's, and Mallet, Wit's End.

Either way, I enjoyed Wit's End. The on-hit MR seemed to work well with his passive, since you've taken a beating but are now gaining all this HP back while having higher resistances.

9/21 masteries for CDR.

I like to play Voli as a tanky DPS not unlike Garen or Warwick with an emphasis on stacking health to feed his W. Typically I grab Mercury Treads or Ninja Tabi depending on the enemy team, then Frozen Mallet, Sunfire Cape, Atma's Impaler, and Spirit Visage. Your last item, like your boots, should depend on the enemy team. If they have a lot of AD go with Frozen Heart. AP, go with Wits End.