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Layered lithium-rich manganese-based materials with high voltage stability and high energy density are used to modify the surface of spent LiCoO 2 materials (LCO) for designing high-performance Li+-storage structures with high specific capacity and high voltage cycling stability. In this typical regeneration process, Mn2+, Co2+, Ni2+, and Li+ acetates were introduced as raw materials for coating Li 1.20 Mn 0.54 Co 0.13 Ni 0.13 O 2 (LLO) on the surface of spent LCO particles uniformly via a sol-gel method. The structural, morphological, and elemental-chemical-state characterisation results indicate that the recycled LLO@LCO materials exhibit a typical core-shell structure, with a layer-structured-Li 1.20 Mn 0.54 Co 0.13 Ni 0.13 O 2 layer ~ 10 nm thick as the high-voltage-stable-shell and a well-ordered layer-LiCoO 2 as the high-capacity-core. As expected, the regenerated LLO@LCO composites show an upgraded Li+-storage performance compared to bare LCO. The optimised LLO@LCO materials show an initial capacity of 197.1 mAh g−1 at 0.1 C, and ~ 95.8% retention after 100 cycles under 3.0–4.5 V at a rate of 1 C. All results indicate that this highly efficient, LLO assisted modification regenerate strategy can be easily extended to regenerate other spent cathodes to synthesise advanced energy storage materials with high voltage cycle stability and high specific capacity. • LLO was introduced for regenerating spent LCO. • LLO@LCO compounds were synthesized via sol-gel method. • Recycled LLO@LCO shows upgraded high-voltage stability. [ABSTRACT FROM AUTHOR]

In this study, Fe 2 O 3 with oxygen vacancies (OVs) introduced by Ti doping is partially wrapped by reduced graphene oxide (rGO), and then grown directly on carbon cloth (CC) to obtain a self-supported electrode with hierarchical structures (Ti-Fe 2 O 3 @rGO/CC). Compared with Fe 2 O 3 nanosheets, Ti-doped Fe 2 O 3 nanosheets show better lithium storage performance because the existence of OVs can not only promote faster charge transfer kinetics but also help to maintain the integrity of electrode structure and improve the electrochemical activity. Especially, the rGO sheets are partially wrapped on Ti-Fe 2 O 3 , inhibiting the agglomeration of components and shortening the diffusion distance of Li+, to obtain better cycle stability. Moreover, it can also provide a buffer to alleviate the volume expansion, avoid the excessive growth of SEI film, and ensure that OVs can maximize their advantages under deep discharge conditions. The Ti-Fe 2 O 3 @rGO/CC electrode delivers a high capacity of 1193 mAh g−1 (3.245 mAh cm−2) at 200 mA g−1, showing great potential as an anode material for lithium-ion batteries. [Display omitted] • Fe 2 O 3 with oxygen vacancies was partially wrapped by rGO and loaded on carbon cloth as self-supported electrode. • The OVs promote fast charge transfer, maintain the electrode integrity and improve the electrochemical activity. • The rGO inhibits excessive growth of SEI film and ensures the OVs to maximize their advantage under deep discharge. • The electrode delivers high Coulomb efficiency and high reversible capacity. [ABSTRACT FROM AUTHOR]

The uneven dispersion of MnO easily leads to local volume change, resulting in the crushing and pulverizing of electrode. Herein, a spongy three-dimensional (3D) porous MnO/C composite was fabricated by pyrolysis of the double-network (DN) aerogel composed of agar (AG) and Mn-crosslinked sodium alginate (SA). The spongy MnO/C composite has homogeneous distribution and uniform size ultrafine MnO nanoparticles embedded into 3D porous carbon network and shows high BET surface area of 363 m2 g−1, which can not only improve the electrical conductivity, but effectively confine the expulsion of MnO and restrain the crushing and pulverizing of electrode. As anode for LIBs, the spongy MnO/C composite exhibits superior rate capability (574 mAh g−1, 2 A g−1) and excellent cycling stability. The capacity gradually increases during the cycling process, reaching 1270 mAh g−1 after 500 cycles at 2 A g−1. The rising capacity can be attributed to the following reasons: 1) more Mn2+ was oxidated to higher valence, 2) The enhanced amorphism of MnO improves Li+ diffusion kinetics, 3) the reversible form and decomposition of SEI. • A spongy three-dimensional porous MnO/C composite was fabricated. • MnO/C composite has homogeneous ultrafine MnO nanoparticles and high BET surface area. • MnO/C composite exhibits excellent rate capability and cycling stability. • MnO/C composite is a potential anode material. [ABSTRACT FROM AUTHOR]

As an alternative to Li-ion batteries, potassium-ion batteries have attracted increasing research interest due to the natural abundance of potassium and low cost. However, the larger ionic radius of the potassium easily causes a large volume expansion of the anode materials, eventually hindering the practical application of potassium-ion batteries. Here, we reported a heteroatomic doping mushroom biomass carbon (HDMC) as anode material for potassium-ion batteries. With high surface area and rich heteroatomic doping (N, S, and P), the as-prepared porous HDMC not only provides sufficient void space to relieve volume expansion of electrode but also offers highly efficient channels for fast transport of both electrons and potassium ions. The results demonstrated that the HDMC showed relatively high specific capacity (290 mAh g−1 at 500 mA g−1) and outstanding cycling stability after 2000 cycles. In-situ Raman spectroscopy and galvanostatic intermittent titration confirmed its surface-dominated potassium storage behavior with fast de-/potassiation kinetics, satisfactory reversibility, and fast ion/electron transport. This work guides an effective bionic strategy for the preparation of biomass carbon as high-performance anode materials. [Display omitted] • Mushroom-derived carbon is employed as anodes for the potassium-ion battery. • HDMC-500 has a high reversible capacity and outstanding rate capability. • H 3 PO 4 promotes the formation of activated and p-doped mushroom biomass. [ABSTRACT FROM AUTHOR]