Hi Gh-Performance Li/Na Hybrid-Ion Batteries with Nonstoichiometric Li2.7v2.1(Po4)3/C As Cathode Material

A novel structure of Li/Na hybrid-ion batteries is proposed, using nonstoichiometric Li 2.7 V 2 .1 (PO 4 ) 3 /C nanocomposites as cathode and Na foil as anode with lithium-ion electrolyte (NSLVP-L). The discharge specific capacity of 132.99 mAh·g -1 is delivered at a current density of 100 mA·g -1 in the voltage range between 2.5 V and 4.2 V, and as high as 108.50 mAh·g -1 when the current density increases to 1000 mA·g -1 , which shows a superior rate performance. A discharge capacity of 87.11 mAh·g -1 can still be observed at the current density of 1000 mA·g -1 in the voltage range between 3.0 V and 4.3 V, which keeps retention rate of 80.42% after 800 cycles. This simple design strategy of hybrid-ion batteries harvests the synergetic contribution of Li + and Na + ions, providing an efficient solution to further improve the battery performance