Slope‐dominated carbon anode with high specific capacity and superior rate capability for high safety Na‐ion batteries

The comprehensive performance of carbon anodes for Na‐ion batteries (NIBs) is largely restricted by their inferior rate capability and safety issue, resulted from the low‐potential plateau region. Herein, a slope‐dominated carbon is achieved at a low temperature of 800 oC, which delivers a high reversible capacity of 263 mA h g‐1 at 0.15C with an impressive initial Coulombic efficiency (ICE) of 80%. Extraordinarily, when paired with the NaNi1/3Fe1/3Mn1/3O2 cathode, the reversible capacity at 6C is still 75% of that at 0.15C, and 73% capacity retention can be obtained after 1000 cycles at 3C. It suggests that the enhanced Na storage performance could be attributed to the unique microstructure with randomly oriented short carbon layers and the relatively higher defect concentration. Given its robustness, such a low‐temperature carbonization strategy (contrast to commonly employed high temperatures) can also be applicable to other precursors and provide a new opportunity to design slope‐dominated carbon anode for high safety low‐cost NIBs with excellent ICE and superior rate capability.

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