Ameliorating electronic/ionic transport and structural stability of electrode materials is important to the development of power-intensive lithium ion batteries. Despite its great potential as a high-power anode, titanium niobium oxide (Ti 2 Nb 10 O 29 , TNO) still underperforms due to its unsatisfactory electronic/ionic conductivity. In this work, a powerful synergistic strategy by combining ion doping and spiral array architecture to boost high-rate performance of TNO is reported. Cr 3+ doped TNO nanoparticles (Cr-TNO) of 5–10 nm intimately grow on a conductive vertical graphene@TiC-C (VGTC) skeleton, forming novel Cr-TNO@VGTC spiral arrays. The unique spiral growth of TNO is achieved due to the confinement effect of VGTC skeleton. Meanwhile, a more open TNO crystal structure with faster ion transfer paths and enhanced structural stability is realized by Cr 3+ doping, demonstrated via density functional theory calculation and in situ synchrotron X-ray diffraction technique. Benefiting from the superior conductive network, enhanced intrinsic electronic/ionic conductivity of Cr-TNO and reinforced structural stability, the Cr-TNO@VTC arrays show prominent high-power performance with a large capacity of 220 mAh g −1 at 40 C (power density of ≈11 kW kg −1 ) and superior durability (91% retention after 500 cycles). This work provides a new path for the construction of widespread high-power electrodes for fast energy storage.
Zhi Nie,Hualin Xiong,Changlong Du,Lei Yu,Lianrui Li,Gengping Wan,Guizhen Wang
Improving electronic and ionic transport and the structural stability of electrode materials is essential for the development of advanced lithium-ion batteries. Despite its great potential as a high-power anode, Ti2Nb10O29(TNO) still underperforms due to its unsatisfactory electronic and ionic conductivity. Here, a TNO/carbon microtube (TNO@CMT) composite is constructed via an ethanol-assisted solvothermal process and controlled annealing. The hollow carbon framework derived from kapok fibers provides a lightweight conductive skeleton and abundant nucleation sites for uniform TNO growth. By tuning precursor concentration, the interfacial structure and loading are precisely regulated, optimizing electron/ion transport. The optimized TNO@CMT-2 exhibits uniformly dispersed TNO nanoparticles anchored on both inner and outer CMT surfaces, enabling rapid electron transfer, short Li+diffusion paths, and high structural stability. Consequently, it delivers a reversible capacity of 314.9 mAh g−1at 0.5 C, retains 75.8% capacity after 1000 cycles at 10 C, and maintains 147.96 mAh g−1at 40 C. Furthermore, the Li+diffusion coefficient of TNO/CMT-2 is 5.4 × 10−11cm2s−1, which is nearly four times higher than that of pure TNO. This work presents a promising approach to designing multi-cation oxide/carbon heterostructures that synergistically enhance charge and ion transport, offering valuable insights for next-generation high-rate lithium-ion batteries.
Nan Luo,Guoliang Chen,Yunfan Shang,Suyang Lu,Jun Mei,Changyu Tang,Zhoukun He,Wenwen Zeng,Haoran Zhan
Ti 2 Nb 1 0 O 2 9 (TNO) is considered as a potential anode material due to its high capacity/power density and reliable safety. However, its poor electronic conductivity restricts its rate performance, which is important for its application in electric vehicles (EVs). In this study, we fabricated a hybrid of Ti 2 Nb 1 0 O 2 9 − x /holey-reduced graphene oxide (TNO x /HRGO) by a two-step method. In the structure of TNO x /HRGO, TNO x microspheres with oxygen vacancies are wrapped by gossamer-like HRGO. The oxygen vacancies of TNO x and the high conductivity of HRGO can effectively enhance the electronic conductivity of the TNO x /HRGO hybrid, and the HRGO holes are beneficial for the transmission of lithium-ion ( Li + ). The synergy effect of above features improves the rate performance of the TNO x /HRGO hybrid. In addition, the existence of HRGO can buffer volume expansion during the insertion processes of Li + , which can improve cyclic stability of the TNO x /HRGO hybrid. Consequently, the TNO x /HRGO electrode has excellent lithium-ion storage capacity, with high-rate performance (242 mAh/g at 10 ∘ C, 225 mAh/g at 20 ∘ C and 173 mAh/g at 40 ∘ C) and excellent cyclic stability (98.0% capacity retention after 300 cycles at 10 ∘ C). This work reveals that TNO x /HRGO can be a potential anode material for high-rate-performance lithium-ion storage.
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