Na-ion-batteries (NIB) are one of the most promising candidates for future low-cost energy-storage technologies. Due to the large size of Na ions, conventional anode materials for Lithium-ion-batteries cannot be used in NIBs. However, nongraphitisable carbons, also called hard carbon, have been found to have good reversible capacities and cycle life when used as the anode material. The storage mechanism of Na ion in the hard carbon has been studied by many workers, but remains controversial with different explanations. We propose to perform neutron total scattering on a series of Na-ion-charged nongraphitisable carbons anodes to probe the behaviour of Na ions in these materials to better understand storage mechanism in the nongraphitizable carbons. The findings will provide theoretical insights for design of high performance hard carbons for NIBs.