Fig. 2: DNP enhancement of Li metal.

a 7Li NMR spectrum of microstructural lithium metal (sample A), with and without 15.6 W of microwave irradiation at 395.29 GHz (μw ON/OFF), recorded at 14.1045 T, 12.5 kHz MAS and a sample temperature of ~300 K, using a Hahn echo pulse sequence, a recycle delay of 0.25 s and 80 scans. Spinning sidebands are marked with an asterisk. b The enhancement of the integrated intensity and peak intensity as a function of the B0 field (sample B), measured at 100 K.