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Polyaniline (PANI) has long been explored as a promising organic cathode for Li-ion batteries. However, its poor electrochemical utilization and cycling instability cast doubt on its potential for practical applications. In this work, we revisit the electrochemical performance of PANI in nonaqueous electrolytes, and reveal an unprecedented reversible capacity of 197.2 mAh g−1 (244.8 F g−1) when cycled in a wide potential range of 1.5 to 4.4 V vs. Li+/Li. This ultra-high capacity derives from 70% -NH- transformed to =NH+- during deep charging/discharging process. This material also demonstrates a high average coulombic efficiency of 98%, an excellent rate performance with 73.5 mAh g−1 at 1800 mA g−1, and retains 76% of initial value after 100 cycles, which are among the best reported values for PANI electrodes in battery applications. [ABSTRACT FROM AUTHOR]

In order to improve the electrochemical properties of nano Si-carbon composites, a binder-free Si-CNTs composite with good dispersion of Si nanoparticles were prepared by ionic liquids self-assembly method. [Display omitted] • A binder-free Si-CNTs composites were prepared by ILs assisted self-assembly method. • The as-prepared Si-CNTs composites show ball-like structure, and the SiNPs are dispersed in the carbon nanotubes self-assembly uniformly. • The carbon nanotubes could be self-assembled into a 3D structure through electrostatic gravitational force of ILs, and the heteroatoms of ILs could dope in the carbon skeleton during annealing. • ILs plays an important role in the dispersion of SiNPs in Si-CNTs system. • Si30%-CNTs exhibit excellent cycle performance and rate capability. Binder-free nano silicon/carbon nanotube composites anodes were synthesized by electrostatic self-assembly of ionic liquids (ILs) and annealing process. The addition of [Emim]Tf 2 N ILs successfully improved the dispersion of silicon nanoparticles (SiNPs) in the carbon nanotubes (CNTs). And the carbon nanotubes could be self-assembled into a 3D structure network through electrostatic gravitational force. Moreover, the wettability of electrode also be improved due to the heteroatoms of [Emim]Tf 2 N ILs doped in the CNTs during annealing. By integrating these advantages, the Si30%-CNTs anodes exhibit a high initial reversible discharge capacity of 2580.3 mAh g−1 at a current density of 0.4 A g−1. Even at a much higher current density of 10 A g−1, the Si30%-CNTs anodes can still deliver a high reversible discharge capacity of 871.1 mAh g−1. The outstanding performances compared to traditional coating method are assigned to that the ionic liquids self-assembly method improves the dispersion of SiNPs. [ABSTRACT FROM AUTHOR]

The spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) material is considered as a promising cathode in high-voltage lithium-ion batteries due to its advantageous voltage and capacity. Previous results indicate that the electrodes constructed by LNMO with the same compositions while differing in the crystallite geometries always exhibit various electrochemical performances. Here, to probe the relationships between the crystalline geometry of the obtained cathodes and their electrochemical properties, we synthesized different facet-exposed LNMOs with the same compositions using a template method. We demonstrate that the crystallite geometries of the hydroxide precursors can be tuned easily via varying the synthesize parameters, while the tuned precursors can be employed as the templates during the final product preparation. LNMOs enclosed by single {111} facets (LNMO-OH) and both {110} and {100} facets (LNMO-HP) are obtained and employed to elucidate the particle geometry-dependent electrochemical properties. Despite better rate capabilities exhibited for LNMO-HP because of the higher lithium diffusion coefficients along these crystal orientations, inferior cycling performance is released compared with its LNMO-OH counterpart. These insights can provide informative guidance in particle geometry-dependent material construction, thus helpful in realizing high-performance LNMO cathode. • Different facet-exposed LNMOs with the same compositions were synthesized. • The crystallite geometries of the hydroxide precursors can be tuned easily via varying the synthesize parameters. • Facet-exposed LNMOs exhibit various electrochemical properties. • Working mechanism of different LNMOs was investigated. [ABSTRACT FROM AUTHOR]

A novel porous structure MnO-SiO x @C composite has been designed and prepared as an anode material for lithium-ion batteries through scalable spray pyrolysis and a subsequent annealing process. XRD, SEM, TEM, Raman, and BET measurements indicate that the MnO-SiO x @C composite displays a spherical mesoporous structure with SiO x particles, embedded in the porous MnO structure combined with carbon coated on the surfaces. The enhanced electrochemical performance can be attributed to the mutual segregation of the heterogeneous oxides of MnO and SiO x during delithiation and the buffer composition region at the origin of uniform carbon layers and abundant nanopores. In addition, the new phase Mn 2 SiO 4 , which is formed in the MnO-SiO x @C composite after 800 ºC, can act as the joint between MnO and SiO x to restrain the strain force originating from the volume change during the charge and discharge process. As a result, the obtained MnO-SiO x @C composite exhibits significantly enhanced electrochemical performance in terms of high Coulombic efficiency, excellent rate capability and good cyclability. • Porous MnO-SiO x @C microspheres was prepared by spray drying method. • MnO-SiO x @C samples show enhanced cycle stability and rate performance. • The Mn 2 SiO 4 phase played key role in improvement the structure stabilities. [ABSTRACT FROM AUTHOR]