CHAPTER 4: Dynamic Nuclear Polarisation Enhanced NMR

Solid-state NMR is playing a very important role in accessing the local structure and dynamics in electrochemical energy storage materials. However, the single greatest challenge faced by NMR is its poor sensitivity that often significantly restricts the type of experiment that can be performed. This chapter provides a general introduction to the field of Dynamic Nuclear Polarisation (DNP) that can enhance the sensitivity of solid-state NMR spectroscopy by multiple orders of magnitude. A brief historical perspective on the field is presented spanning its discovery in the 50s to today's development. This is then followed by a theoretical description of the various DNP mechanisms and polarisation transfer pathways to obtain optimum efficiency under a range of conditions. An overview of the required instrumentation, experimental conditions, most effective polarising agents currently used and key aspects for DNP sample formulation are also given.