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Pre-lithiation technology is essential to improve the initial coulombic efficiency (ICE) and cycling stability of high SiO x content cells. Different amounts of pre-lithiation significantly affect the electrochemical performance of cells. In this study, three groups of LiNi 0.8 Co 0.1 Mn 0.1 O 2 || SiO x /Graphite pouch cells (SiO x , 45 wt%) with different pre-lithiation amounts are fabricated using an electrochemical pre-lithium method. The effects of pre-lithiation amounts on the capacity and cycling stability are comprehensively investigated by non-destructive tests and post-mortem analysis. The results show that increasing the amounts of pre-lithiation can substantially improve the capacity of the cells, but may also accelerate their aging. Further studies reveal that the cycling stability of SiOx/Graphite anode is strongly affected by the amounts of pre-lithiation, whereas the effect on the cathode is negligible. Moreover, titration gas chromatography (TGC) experiments are used to quantify the lithium loss in SiO x /Graphite anode. The accelerated formation of SEI and trapped lithiated active materials as well as lithium dendrites caused by over-lithiation at SiO x /Graphite anode are responsible for the rapid degradation of pouch cells with high pre-lithiation amounts. This work demonstrates the complex relationship between pre-lithiation amounts and electrochemical performance, which needs to be carefully measured in SiO x -based cells. [Display omitted] • NCM811||SiO x /Graphite pouch cells with different pre-lithiation amounts are evaluated. • Both ICE and cycle stability is greatly influenced by the pre-lithiation amount. • The amounts of pre-lithiation have little effect on the aging of the cathode. • High pre-lithiation amounts can accelerate anode aging. • Titration gas chromatography is used to quantify the lithium loss in anode. [ABSTRACT FROM AUTHOR]

• The N-doped carbon nanotubes (N-CLNTs) were prepared through the carbonization of PANI nanotubes. • The N-CLNTs possesses 3D interconnected networks with unique 1D tubular structure. • The N-CLNTs-700 exhibits excellent cycling stability. • The excellent performance of N-CLNTs-700 attribute to multiple synergistic effects. Potassium-ion batteries (PIBs), as an inexpensive alternative to lithium-ion batteries (LIBs), have attracted significant attention for large-scale energy storage owing to their high capacity and low cost. The polyaniline (PANI) is a promising carbon source for high-performance PIBs anodes because of its diversity of morphologies and high N content. However, the PANI-derived carbon is rarely utilized as PIBs anode. Herein, the cross-linked porous N-doped carbon nanotubes (N-CLNTs) were prepared through the carbonization of PANI nanotubes. By adjusting the carbonization temperature, the N-CLNTs with different N content were designed to systematically elaborate on the effect of the N-doping on the electrochemical properties for PIB anodes. Owing to the synergistic effect of the high N-5/N-6 content and unique 1D tubular structure, the N-CLNTs-700 delivers a reversible capacity of 261 mAh g−1 at 0.05 A g−1 after 150 cycles and can still remain 168 mAh g−1 at 2 A g−1 over 3000 cycles. These results shed light on the design of carbon materials to efficiently enhance the electrochemical performance of PIBs. [ABSTRACT FROM AUTHOR]

Potassium-ion batteries (PIBs) are in the spotlight as a possible alternative to lithium-ion batteries. Graphitic carbons are promising anode materials for PIBs due to their low-plateau potential that is beneficial for the realization of high-voltage full cells. However, inferior cycling stability hinders their practical application. Herein, highly graphitized carbon nanofibers (HG-CNFs) as a free-standing electrode are served as the anode for PIBs. The HG-CNFs exhibits a reversible capacity of 200 mAh g−1 at the plateau potential below 0.2 V (76% of total capacity) and superior rate performance with a depotassiation capacity of 226 mAh g−1 at 35 C. Moreover, the capacity decay of HG-CNFs is less than 0.008% per cycle during 400 cycles, which is superior to those of most other graphitic carbons. The excellent electrochemical performance of HG-CNFs is attributed to its merits of free-standing fibrous networks and graphitic structure with rational defects that alleviate the volume expansion incurred by K+ intercalation. • Highly graphitized carbon nanofibers as a free-standing electrode was prepared. • The interconnected networks improve the integrity and buffer the volume expansion. • The HG-CNFs exhibits a capacity of 200 mAh g−1 at the plateau potential below 0.2 V. • The HG-CNFs shows outstanding cycling performance in K-ion half-cells. [ABSTRACT FROM AUTHOR]

Developing a high‐rate and stable battery‐type anode to match the capacitor‐type cathode is a critical issue for potassium ion capacitors (PICs). Surface‐redox pseudocapacitive materials can meet this demand due to their fast surface Faradaic reaction kinetics and superior structure stability during charging–discharging. Herein, a free‐standing anode by growing VN particle‐composed nanosheets on carbon fibers (VN@CFs) is developed. The VN@CFs is endowed with high reversible capacity of 245.8 mA h g–1 at 0.05 A g–1, high rate performance of 102.7 mA h g–1 at 6.0 A g–1, and long‐term stability. Based on the in situ XRD, ex situ XPS and TEM characterizations, and density functional theory calculations, it is proved that the potassium storage of VN derives from a surface‐redox pseudocapacitive mechanism between VN and K+, rather than an intercalation or conversion reaction. As expected, the as‐assembled PICs based on the VN@CFs anode show an ultrahigh power output of 10.9 kW kg–1 when keeping an energy density of 49.2 Wh kg–1 and excellent capacity retention of 86.8% after 15000 cycles. [ABSTRACT FROM AUTHOR]

Nanometerization of tin-based materials is beneficial to alleviate the volume effect, and thus improving the cycle stability of tin-based materials. Meanwhile, the smaller size can enhance the reversibility of the conversion reaction, which is crucial for increasing the capacity of tin-based materials. Therefore, reducing the size of tin-based materials may bring the advantages of cycle stability and specific capacity. In this work, we tried to disperse tin ions with organic skeleton to maximize the dispersion of active materials. Tin-based anode material based on polyethyleneimine‑sodium xanthogenate is synthesized by in-situ method at room temperature, and the thiocarboxyl group of polyethyleneimine‑sodium xanthogenate greatly increases the dispersion of metal ions. Carbon nanotubes (CNTs) are further introduced to improve the conductibility of tin-based materials owing to the existence of non-conductive organic groups. The anode material exhibits a long cycle life which delivers a specific capacity of 560 mAh g−1 after 1000 cycles. By analyzing the differential charge capacity (dQ/dV) curves, we find that the conversion reaction of tin-based materials is highly reversible. Polymers skeleton is introduced into tin-based materials as the anode material for lithium ion battery and the conversion reaction of tin-based material exhibits an excellent reversibility. Unlabelled Image • Polymers skeleton is introduced into tin-based materials as the anode material for lithium ion battery. • Electrode material is synthesized at room temperature without a crystallization process. • Conversion reaction of tin-based material exhibits an excellent reversibility. • The composite electrode material exhibits a long cycle life up to 1000 cycles. [ABSTRACT FROM AUTHOR]

• Tin-based organic sulfide is synthesized at room as anode materials. • Conversion reaction of the Tin-based material exhibits excellent reversibility. • Maintaining the metal-organic structure is conducive to the reversible conversion reaction Increasing the degree of dispersion is of great significance for improving the electrochemical performance of tin-based materials. The smaller size is conducive to alleviating the volume effect and improving the reversibility of the conversion reaction, thus improving the cyclic stability and reversible capacity of tin-based anode materials. In this work, tin-based organic sulfide is synthesized by potassium ethyl xanthate, and graphene is added to enhance the conductivity of the electrode material. The anode material exhibits excellent performance with the residual capacity of 657 mAh g−1 after 400 cycles at the current density of 200 mA g−1. The differential charge capacity (dQ/dV) curves show that the conversion reaction of electrode materials has good reversibility and is maintained until the end of the cycle. We also investigated the effect of calcination temperature on the conversion reaction, and verified that it is important to maintain the tin-organic structure for the reversibility of the conversion reaction. Image, graphical abstract [ABSTRACT FROM AUTHOR]