No investment is “risk free”. The closest thing to risk free that exists, and is commonly used in textbooks as the “risk free” rate, is the U.S. t-bill.

And these are currently offering rates far lower than 11% (more like .5% yields).

A debt mutal fond (or bond mutual fund) has less risk than an equities mutual fund, however, less risk implies less expected return.

There is a postive relation between risk and expected return. The higher the risk, the higher the expected return.

While it is all said and done, looking back, there may have been investments that substantially outperformed other investments.

However, looking forward, there do not exist investments that have Low Risk, High expected return. That is just not how it works. If such an investment existed, everyone would flock to them driving down the expected return.

What all this means is finding a bond fund with an annual return of 11-15% that is risk free is simply not going to happen, because it does not exist.

There is a great deal of risk in debt mutual funds. The main risk will be a rise in interest rates. When that should happens, their values will evaporate. At the moment 11-15% returns on such funds is probably not possible. It was possible back in March, but not now. There probably will not be a significant rate increase for the next 12 months but there might be. A junk bond fund would provide the possibility of the highest return but the risk is very great indeed. There indeed are some that currently pay at least 11%. I am not sure that I would recommend them, but they do exist.

Pioneer Diversified High Yield–HNW comes closest to meeting your goal with a reasonable chance of not loosing too much in the process. It yields about 10.7% but has cut its dividend a couple of times during the past year. But its maturities are not too far out and it portfolio quality is not extremely risky although it certainly is no where near investment grade either.