Yes. All Campbell Scientific dataloggers currently have nonvolatile memory. Nonvolatile memory was added to the CR10X in 1996. All datalogger models introduced since then have included nonvolatile memory.
Nonvolatile memory is reliant on the 3 V lithium battery inside the datalogger. As long as this internal battery has a charge above 3 V, no data should be lost if the datalogger loses power.