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It is of great importance to develop high‐capacity electrodes for sodium‐ion batteries (SIBs) using low‐cost and abundant materials, so as to deliver a sustainable technology as alternative to the established lithium‐ion batteries (LIBs). Here, a facile ball milling process to fabricate high‐capacity SIB anode is devised, with large amount of amorphous SeP being loaded in a well‐connected framework of high‐conductivity crystalline graphene (HCG). The HCG substrate enables fast transportation of Na ions and electrons, while accommodating huge volumetric changes of the active anode matter of SeP. The strong glass forming ability of NaxSeP helps prevent crystallization of all stable compounds but ultrafine nanocrystals of Na2Se and Na3P. Thus, the optimized anode delivers excellent rate performance with high specific capacities being achieved (855 mAh g−1 at 0.2 A g−1 and 345 mAh g−1 at 5 A g−1). More importantly, remarkable cycling stability is realized to maintain a steady capacity of 732 mAh g−1 over 500 cycles, when the SeP in the SeP@HCG still remains 86% of its theoretical capacity. A high areal capacity of 2.77 mAh is achieved at a very high loading of 4.1 mg cm−2 anode composite. [ABSTRACT FROM AUTHOR]

Severe deviation in structure and chemistry at grain boundaries has been regarded as the source of the poor conductivity of Li 3 x La 2/3 -x TiO 3. In this work, we report an in situ grain boundary engineering method to address this bottleneck. A lithium-rich electrolyte, Li 3 OCl, was introduced into Li 3 x La 2/3- x TiO 3 to replenish lithium at the grain boundaries. Both the Li-gain on the boundary and generation of a Li-rich grain-engineered layer contributed to an optimized grain boundary conductivity of 1.52 × 10−4 (S/cm) and a depressed activation energy of 0.32 eV for grain boundary. Full batteries were further employed to demonstrate the enhancement in conductivity. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Different configurations of Sn and C films were deposited and used as a planar anode for Li ion battery. The interplay of carbon layer with Sn as supporting and buffering, respectively, was revealed. The suppression on the allotropic transformation to α phase by a carbon layer results in a significantly improved capacity retention rate, which also avoids the crack of Sn film. As expected, a conductive carbon layer improves rating performance. However, a supporting carbon layer (SC) just contributes to the charge transfer process. A DFT approach was used to assess the allotropic transformation process. An additional barrier (∼0.86 eV) exits on the α-β diagram, which is responsible for the irreversibility of α phase back to β phase. An enhanced persistence of β phase in Sn/C anode contributes to cycling performance. A Li rich condition contributes to the stabilization of β-Sn, which is thermodynamically favored. A nano buffering carbon (BC) layer can evidently alleviate the side reaction on Sn surface, which in turn promotes the diffusion of Li ions in electrode and generates a Li rich condition. The direct contact of Sn with electrolyte leads to serious accumulation of α-Sn during cycling and results in a poor cycling performance. By the synergistic effect of BC and SC, a sandwich C/Sn/C structure demonstrates an enchantment in electrochemical behavior. [ABSTRACT FROM AUTHOR]

This work reviews national and international treatment methods of cathode materials commercially available in recent years, such as hydrometallurgy, pyrometallurgy, and direct regeneration, supplemented by studies of innovative external field processes and electrochemical method. Analyzing the recycling characteristics and failure mechanisms provides a valuable reference for the recycling research of lithium-ion batteries. [Display omitted] • The failure mechanisms and recycling characteristics of three LIBs types (LFP, NCM, LMO) are described in detail. • The applications of main recycling methods for different LIBs are summarized. • Differences in LIBs recycling methods were systematically analyzed from recycling effectiveness, economy, and environment. • Optimal solutions for various LIBs recycling methods are pointed out, and insights for future development are provided. Lithium-ion batteries (LIBs) have brought undeniable technological innovation to electronic devices, and the widespread use of these batteries has led to significant production of raw materials. However, these materials need to be properly treated to eliminate the negative environmental impact of toxic raw materials. Recycling of such batteries requires necessary and appropriate solutions. Therefore, this work reviews national and international treatment methods of cathode materials commercially available in recent years, such as hydrometallurgy, pyrometallurgy, and direct regeneration, supplemented by studies of external field process and electrochemical method, which are innovative and environmentally friendly methods of recycling. It also includes the recycling characteristics and failure mechanism of spent LiFePO 4 , LiNi x Co y Mn z (x + y + z = 1), and LiM x O 2x (x = Ni, Co, Mn), respectively. Additionally, considering the future challenges and opportunities of post-consumer LIBs recycling, this work aims to provide a valuable reference for LIBs recycling. [ABSTRACT FROM AUTHOR]

In this study, Li 0.35 La 0.55 TiO 3 (LLTO) was coupled with Al-doped lithium lanthanum zirconate (LLZO) to improve the grain boundary and total conductivity. The obtained ceramic pellets (LLTZO) demonstrated a recordable grain boundary and total conductivity of 3.41 × 10−4 and 3.03 × 10−4 S/cm, respectively. The obtained results establish that the heteroatoms can perturb the cation ordered structure and improve the 3D conductivity in grain bulk. In addition, the residual Al-doped LLZO on the grain boundary led to a decline in the boundary resistance. An LiFeCoPO 4 |Li cell was adopted to demonstrate the enhanced conductivity of LLTO. The solid state battery rendered a specific capacity of over 101.2 mAhg−1 after 300 cycles at a relatively high rate of 0.5C. It is established from the experiments that manufacturing a solid battery using the all-coating technique provides a promising approach to achieve a practical application. [ABSTRACT FROM AUTHOR]

Nickel phosphide (Ni 3 P) is a promising anode material for lithium-ion batteries owing to its high specific capacity, though significant improvement in its cycling stability is highly desired. Here we propose an effective and low-cost solution via a three-dimensional construction of porous NiO covered Ni 3 P films over a substrate of Ni foam, through electroless plating of P-rich Ni 3 P and subsequent in situ oxidation in air. The in situ oxidation of P-rich Ni 3 P resulted in the formation of nano porous NiO capping layer. Remarkable enhancement in the cycling stability of such a composite anode was thus realized. The initial discharge capacity for a CR2016-type coin cell was as high as 920 mA h g −1 , and there was still a reversible capacity of 550 mA h g −1 after 60 cycles at a current density of 38.8 mA g −1 . The presence of porous NiO capping layer changed the lithiation path and significantly improved the cycling performance. The decreased resistance in charge transport due to the existence of adequate channels for Li ions diffusion also enhanced rate performance. A pristine Ni 3 P films was researched as a comparison. [ABSTRACT FROM AUTHOR]

A novel strategy was employed to introduce a carbon layer on Si particle to overcome the intrinsic poor electrical conductivity and significant volume change. The carbon layer was fabricated by forming polyphosphazene coating through a facile precipitation polymerization method, followed by carbonization. As a result of formation of core-shell structure, the Si anode exhibited improved cycling stability (740 mA h/g remained after 100 cycles) and rate capability (300 mA h/g at a rate 2C). In addition, 99% coulombic efficiency was remained after 100 cycles. [ABSTRACT FROM AUTHOR]