Lithium transition metal nitrides Li3-xMxN (M=Co, Ni and Cu) have been reported previously as promising anodes for Li-ion batteries. The most promising compound in this family is Li2.6Co0.4N with a large capacity of 760mAh/g2. However, Li2.6Co0.4N does not show satisfactory capacity retention upon long cycles. Following our successful MW synthesis of a range of Li3-x-yMxN nitridometallates with the Li3N structure and in our pursuit of novel materials with improved cycleability and reduced toxicity and cost, we succeeded in the MW synthesis of new co-doped lithium nitrides. In this application we seek 2 days on POLARIS to fully characterise a full range of quaternary Co and Ni materials for the first time; relating defect structure and Li+ ion mobility to the MW synthesis conditions. Structure-property correlations can then be made with ex-situ electrochemical measurements.