A porous carbon based on the surface and structural regulation of wasted lignin for long-cycle lithium-ion battery

Lignin, as the second most abundant source in nature, is considered as a good precursor for hard carbon. However, direct carbonization of pure lignin leads to low surface area and porosity. Herein we develop a method to prepare lignin-based porous carbon by a self-template method assisted with surface modification. The oxygen-containing functional groups are introduced to regulate the surface chemistry of lignin. And the metal ions are chosen to coordinate with the oxygen-containing group in the lignin, which can form the carbonates to act as the self template to regulate the pores structure. The aromatic skeleton of lignin can also disperse the metal ions to bring uniform pore-forming sites. The results show that the carbonized lignin modified by chloroacetic acid (CCL) shows mesopores with surface area of 233.4384 m² g^-1. As anode for lithium-ion batteries (LIBs), the CCL shows a specific capacity of 500 mAh g^-1 at 50 mA g^-1. The capacity retention was 99 % after 1000 cycles at 1000 mA g^-1, which are superior to most reported carbon anode. This work proposes a low-cost anode for LIBs and put forward a regulation strategy for bio-mass carbon. Besides, it would reduce the discard of lignin and alleviate the pollution.

Going Nano with Confined Effects to Construct Pomegranate-like Cathode for High-Energy and High-Power Lithium-Ion Batteries

Pomegranate-like Li₃V₂(PO₄)₃@C (LVP@C) cathode materials are fabricated through confined effect helped by the vacuum-assisted capillary action. The performance of Li_xV₂(PO₄)₃ (x = 0-5) at an extended working voltage of 1.2-4.8 V has been studied by operando X-ray powder diffraction and hybrid functional density functional theory (DFT) calculation. The DFT calculation results suggest that Li₃V₂(PO₄)₃ can be intercalated with another two Li⁺ with a stable crystalline structure, which improves the specific capacity of LVP significantly. The cathode exhibits a specific capacity of 320 mAh g^-1 with an energy density of 736 Wh kg^-1, which is one of the best performances for intercalation cathode materials for Li-ion batteries to our knowledge. Besides, the cathode showed excellent rate capability. In the working potential of 3.0-4.8 V, it exhibits a high specific capacity of 195 mAh g^-1 at 0.2 C, and even at a high rate of 30 C, it still delivers the specific capacity of 145 mAh g^-1 with a power density of 15.93 kW kg^-1. The good performance is mainly attributed to the unique pomegranate structure, which can provide continuous three-dimensional conductive networks for fast electron and Li-ion transfer. This paper provides a new strategy for synthesizing other cathode or anode materials with high energy and power density.

Polyanion-Type Electrode Materials for Sodium-Ion Batteries

Sodium-ion batteries, representative members of the post-lithium-battery club, are very attractive and promising for large-scale energy storage applications. The increasing technological improvements in sodium-ion batteries (Na-ion batteries) are being driven by the demand for Na-based electrode materials that are resource-abundant, cost-effective, and long lasting. Polyanion-type compounds are among the most promising electrode materials for Na-ion batteries due to their stability, safety, and suitable operating voltages. The most representative polyanion-type electrode materials are Na3V2(PO4)3 and NaTi2(PO4)3 for Na-based cathode and anode materials, respectively. Both show superior electrochemical properties and attractive prospects in terms of their development and application in Na-ion batteries. Carbonophosphate Na3MnCO3PO4 and amorphous FePO4 have also recently emerged and are contributing to further developing the research scope of polyanion-type Na-ion batteries. However, the typical low conductivity and relatively low capacity performance of such materials still restrict their development. This paper presents a brief review of the research progress of polyanion-type electrode materials for Na-ion batteries, summarizing recent accomplishments, highlighting emerging strategies, and discussing the remaining challenges of such systems.

Investigations on Zr incorporation into Li3V2(PO4)3/C cathode materials for lithium ion batteries

Zr-modified Li₃V₂(PO₄)₃/C composites (LVZrP/C and LVP/C-Zr) obtained from different ways exhibit enhanced performance, in which Zr exists not only in the LVP lattice but also on the LVP surface.

One-pot synthesis of 3D hierarchical porous Li3V2(PO4)3/C nanocomposites for high-rate and long-life lithium ion batteries

A hierarchical porous Li₃V₂(PO₄)₃/C nanocomposite with excellent cycle stability is fabricated via a simple one-pot process.

Layered hybrid phase Li2NaV2(PO4)3/carbon dot nanocomposite cathodes for Li+/Na+ mixed-ion batteries

Hybrid phase Li₂NaV₂(PO₄)₃ (H-LNVP) is one of the most promising cathode materials for Li⁺/Na⁺ mixed-ion batteries.

Improved electrochemical performance of a Li3V2(PO4)3 cathode in a wide potential window for lithium-ion storage by surface N-doped carbon coating and bulk K-doping

The electrochemical performance of a Li₃V₂(PO₄)₃ cathode in a wide potential window for lithium-ion batteries is improved by combination of surface N-doped carbon coating and bulk K-doping.

Investigation of Co-incorporated pristine and Fe-doped Li3V2(PO4)3 cathode materials for lithium-ion batteries

Co was first employed to modify Fe-doped Li₃V₂(PO₄)₃/C. Under the common effect of doping and a hybrid layer (C + CoO + FeO) coating, the as-obtained composite showed a remarkable rate capability and low capacity fading.