Preparation Of Advanced Carbon-based Materials/Structures And Application For Sodium-ion Hybrid Capacitors

Owing to the widespread distribution and low cost of sodium resources,sodium-ion hybrid capacitors?SIHCs?which take into account both the high energy density of the battery and the high power density of the capacitor,have attracted widespread attention.Currently,it is still a huge challenge with SIHCs finding anode materials that match dynamic of high performance cathode materials.The carbon-based electrode material are considered to be the most promising sodium storage electrode material because of its low sodium-platform,high specific capacity,excellent cycle stability,rich natural content and simple preparation process of carbon materials.The morphology and structure of carbon materials are considered to be the main factors affecting their electrochemistry.This paper focuses on the preparation of carbon anode materials with controlled morphology and structure,and heteroatoms modification.At the same time,we systematically studied the effects of morphology structure and heteroatom-doped carbon on the performance of sodium ion half-cell and sodium-ion hybrid capacitors.This paper mainly includes the following two aspects:?1?We report a nanotube-like hard carbon?NTHC?anode material with high-performance prepared by high-temperature annealing?1150°C?of polyaniline?PANI?precursors.Such NTHC anode shows a high reversible capacity of 419.5 mA h g^-1 at 0.05 A g^-1 and a good rate performance of 74.6 mA h g^-11 at 2.5 A g^-1 in a potential window of 0-2 V?vs Na/Na⁺?.Moreover,a high performance dual-carbon SIHC using such NTHC as anode and activated polyaniline-derived carbon?APDC?as cathode is fabricated,which exhibits a superhigh energy density of 133.0 W h k g^-1 at 2850 W kg^-1 and still remains 100.9 W h kg^-1 at 14250 W kg^-1.In the voltage window of 1.5-3.5 V,this dual-carbon SIHC is able to achieve an overlong cycling life tested at 2 A g^-1,with a good capacity retention of 82.5%even after 12 000 cycles.?2?Herein,we report NS co-doped amorphous nanotube-like carbon?NS-NTC?with N and S contents of 1.58 at.%and 1.01 at.%by pyrolysis high S-loaded polyaniline?PANI?.As a result,the assembled sodium ion half-cell with NS-NTCs serve as anode,which shows a high reversible capacity of 304.8 mA h g^-1 at 0.2 A g^-1 and an excellent rate performance of 124.8 mA h g^-1 at 10 A g^-1 in a voltage window of 0.01-2.5 V?vs Na/Na⁺?.We use nitrogen-sulfur double-doped carbon?NS-NTCs?as anode and a high-capacity activated carbon?APDC?as cathode to assemble SIHCs,which exhibits an ultrahigh energy density of 100.2 W h kg^-1 at 250 W kg^-1 and still remains 50.69W h kg^-1 at 12500 W kg^-1.In addition,this SIHC is able to display good capacity retention and an outstanding capacity retention ratio?72%even after 1500 cycles?at 2 A g^-1.