In the end, it's the billable deliverables and spent hours which generate income for the company and, hence, enables your paycheck.
Most of the times, it's by practicing on new technologies that resources will be more likely to learn and develop skills on it.
The main issue with your question is that you ask for resources to learn and develop their skills without committing some time, which is an oxymore.
They'll need to commit time into this objective so the main idea is to mix project realization and skills enhancing on new techs.
In order to allow our resources to innovate, do some tech-watch and to leverage their skills, we used to (in an AGILE context):
- put 10% of the team velocity in improvement while doing the sprint calculation. These 10% could be used either to recover some of the technical debt or to PoC (perform a proof of concept) more innovative solutions of something done already (hence maybe using new technologies)
- add an innovation sprint of 1 week for each Program Increment (SAFE methodology) in which resources could draw from a list of business needs and realize a solution supposed to be 'innovative'
- Organize internal contests (on their free time; not to do during the project) during which several teams could compete on given topics with a prize to win. An example could be "How would you concieve the meetings of the future ?" in which you can implement IoT, gamification, etc...
- Incitate proactivity and out-of-the-box mindset. If resources detect an answer to a need that can use new concepts/techs/frameworks/[...] that provides value with least risk, they should be able to propose it and PoC it.
- have a recurring meeting in which developers could share with the community some things they learned or discovered which could be used in the project.
- Time is needed to develop skills and learn new things. Money can't insert knowledge in a brain without time associated
- You can mix projects needs with the implementation of innovative solutions if it's not to risky and doesn't destroy the planning
- Resources can deliver a higher value with those innovative solutions and learn at the same time
- In last resort, you can organize a contest with a prize to which teams can participate during their free time upon their will