Extremely high capacity hard carbon for Na-ion battery, delivering 478 mAh g À1 , is successfully synthesized by heating a freeze-dried mixture of magnesium gluconate and glucose by a MgO-template technique. Influences of synthetic conditions and nano-structures on electrochemical Na storage properties in the hard carbon are systematically studied to maximize the reversible capacity. Nano-sized MgO particles are formed in a carbon matrix prepared by pre-treatment of the mixture at 600 8C. Through acid leaching of MgO and carbonization at 1500 8C, resultant hard carbon demonstrates an extraordinarily large reversible capacity of 478 mAh g À1 with a high Coulombic efficiency of 88 % at the first cycle.

An in-depth investigation of the overlithiation/oversodiation and subsequent delithiation/desodiation of graphite and hard carbon electrodes in the first cycle was conducted using operando7Li/23Na solid-state NMR.

No abstract

Extremely high capacity hard carbon for Na-ion battery, delivering 478 mAh g À1 , is successfully synthesized by heating a freeze-dried mixture of magnesium gluconate and glucose by a MgO-template technique. Influences of synthetic conditions and nano-structures on electrochemical Na storage properties in the hard carbon are systematically studied to maximize the reversible capacity. Nano-sized MgO particles are formed in a carbon matrix prepared by pre-treatment of the mixture at 600 8C. Through acid leaching of MgO and carbonization at 1500 8C, resultant hard carbon demonstrates an extraordinarily large reversible capacity of 478 mAh g À1 with a high Coulombic efficiency of 88 % at the first cycle.

No abstract