The best way is to probably relate aspects of pokemon to academic subjects and then to bullshit on how it would help stimulate/develop skills useful in those areas.
E.g.
Economics - allocating scarce resources (EVs) to suit needs/whatever. Making decisions to control something, taking into account opportunity cost
Maths - Damage formula, estimation of damage mentally
History - Drawing in evidence and coming to a decision (what move to make from what your opponent is doing)
There's also the general rationale improvement which can be useful in communication subjects e.g. English as it forces you to think in a logical order under stress, useful perhaps in essays.
Also STRESS that it isn't some fanboy shit but proper competitive stuff, I think your dean probably has the misconception its all going to be "check out my pikachu"
You could also try showing a video battle (find one on youtube) of shoddy or netbattle and I agree with Max you need prospective visitors to the club.