Nanoengineering S-Doped TiO₂ Embedded Carbon Nanosheets for Pseudocapacitance-Enhanced Li-Ion Capacitors

Abstract

Li-ion capacitors, comprising a battery anode and a supercapacitor cathode, have been expected to bridge the gap between batteries and supercapacitors. However, the kinetics mismatch between the anodic sluggish insertion and the cathodic capacitive process has impeded the energy-storage potential of devices. Developing pseudocapacitive anode materials is urgently needed in that pseudocapacitance can deliver energy in the same time scale as electrostatic adsorption and offer a comparable level of energy storage to that of battery-type materials. Here we demonstrate an inside and outside synergistic nanoengineering strategy to synthesize nanoporous carbonmodified S-TiO 2 hybrid nanosheets, through which both the carbon layer and sulfur doping can be simultaneously generated in situ. Benefiting from the in situ S doping, the electronic and ionic conductivity of anatase TiO 2 nanoparticles is enhanced. The carbon-modified S-TiO 2 with dominant pseudocapacitance realizes an unprecedentedly high capacity of 550 mAh g −1 at 0.3 C and excellent rate capability, outperforming that of the ever-reported TiO 2 -based materials. Furthermore, a hybrid Li-ion capacitor based on the as-obtained carbon-modified S-TiO 2 electrode has been assembled, delivering a high energy density of 92.7 Wh kg −1 and power density of 26 kW kg −1 with a stable cycling life (85.8% after 10 000 cycles). Our work offers a new avenue for achieving electrode materials with extrinsic pseudocapacitance that is kinetically comparable to capacitive materials.

Tuning electronic structure of δ-MnO2 by the alkali-ion (K, Na, Li) associated manganese vacancies for high-rate supercapacitors

“…Turing the atomic and electronic structures have been certificated as an efficient way to enhance the intrinsic conductivity of electrode materials, such as doping [17] or coupling [18]. Among the strategies for structural regulation, atomic defect engineering, especially the introduction of vacancies defects, has been recognized as an effective method for adjusting the atomic and electronic structures of electrodes [19].…”

Electrostatically Fabricated Three-Dimensional Magnetite and MXene Hierarchical Architecture for Advanced Lithium-Ion Capacitors

“…In particular, the asfabricated LICs can deliver a large energy density of 130 W h kg −1 at 250 W kg −1 , retain 31 W h kg −1 at 25 kW kg −1 (Figure 5e), and has 86.5% of capacity retention for 5000 cycles (Figure 5f). The electrochemical performance of such LICs are highly comparable to many of the prior arts, including graphite//AC, 1 Nb 2 O 5 //AC, 4 LTSO-C//AC, 27 AC//LFV-GC, 52 Co 3 ZnC@NC//AC, 53 HDMPC//HDMPC, 54 STO-C//AC, 55 BiVO 4 //PRGO, 56 MnO@C//AC, 57 AMC//AC, 58 Li 3 VO 4 //AC, 59 GCNT//GCNT, 60 MnNCN//AC, 61 LTO// AC, 62 MXene//LNMCO, 63 MnO-C//CNS, 64 GCY//AC, 65 TiC//AC, 66 rGO//rGO, 67 and MnFe 2 O 4 //AC 68 (Table S5).…”

Optimization of structural expansion and contraction for TiS2 by controlling the electrochemical window of intercalation/delithiation

“…The electrode materials in lithium-ion batteries (LIBs) are closely related to the energy density and power density [1][2][3]. TiS 2 as the anode material with a four-electron electrochemical reaction demonstrated a high theoretical capacity density of 956 mAh g -1 [4,5].…”