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Sodium ion batteries are an emerging candidate to replace lithium ion batteries in large-scale electrical energy storage systems due to the abundance and widespread distribution of sodium. Despite the growing interest, the development of high-performance sodium cathode materials remains a challenge. In particular, polyanionic compounds are considered as a strong cathode candidate owing to their better cycling stability, a flatter voltage profile, and stronger thermal stability compared to other cathode materials. Here, we report the rational design of a biomimetic bone-inspired polyanionic Na3V2(PO4)3-reduced graphene oxide composite (BI-NVP) cathode that achieves ultrahigh rate charging and ultralong cycling life in a sodium ion battery. At a charging rate of 1 C, BI-NVP delivers 97% of its theoretical capacity and is able to retain a voltage plateau even at the ultra-high rate of 200 C. It also shows long cycling life with capacity retention of 91% after 10 000 cycles at 50 C. The sodium ion battery cells with a BI-NVP cathode and Na metal anode were able to deliver a maximum specific energy of 350 W h kg−1 and maximum specific power of 154 kW kg−1. In situ and postmortem analyses of cycled BI-NVP (including by Raman and XRD spectra) HRTEM, and STEM-EELS, indicate highly reversible dilation–contraction, negligible electrode pulverization, and a stable NVP-reduced graphene oxide layer interface. The results presented here provide a rational and biomimetic material design for the electrode architecture for ultrahigh power and ultralong cyclability of the sodium ion battery full cells when paired with a sodium metal anode. [ABSTRACT FROM AUTHOR]

LiTiO 2 film-coated layered LiNi 0.815 Co 0.15 Al 0.035 O 2 (NCA) material was successfully synthesised through in situ hydrolysis–lithiation to improve electrochemical properties. Herein, NCA was synthesised using solid state reaction, coated by hydrolysis of tetrabutyl titanate and subjected to lithiation process. The optimal molar ratio (LiTiO 2 : NCA) was found to be 1.0 mol%, and the thickness of LiTiO 2 film coated on the surface of NCA of 18 nm was observed through HRTEM images. Compared with pristine NCA, 1.0 mol% LiTiO 2 -coated NCA demonstrated better electrochemical performance with larger capacity of 20 mAh g−1 under 1 C after 100 cycles. Its related capacity retention was 90.8%. The 1.0 mol% LiTiO 2 -coated sample exhibited high discharge capacity of 157.6 mAh g−1 at a current rate of 10 C, whereas the pristine sample only presented 145.3 mAh g−1. The considerably improvement of the rate and cycling properties of the NCA cathode material is achieved using LiTiO 2 as a Li+-conductive coating layer. These new findings contribute towards the design of a stable-structured Ni-rich material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Simple and environment-friendly recovery of valuable metals from spent LIBs was explored. The experimental method, which included reduction roasting and hydrometallurgical recovery, is called a quasi-reversible process. The principle behind the quasi-reversible model could be used to assess the energy consumed during the recovery of metals from cathode active materials. The roasting process was analysed using TG–DSC and Kissinger equation. XRD patterns and mass loss ratios were used to investigate the layered LiNixCoyMnzO2 that broke into Li2CO3, MnO, NiO, Ni and Co. Roasting temperature, coke dosage and roasting time were assessed to determine the leaching efficiency of Li, Ni, Co and Mn. Results indicated that the optimum roasting conditions were roasting temperature of 650 °C, coke dosage of 10% and roasting time of 30 min. The roasted products under the optimum parameters were used to leach the valuable metals, and the leaching efficiencies of Li, Ni, Co and Mn were 93.67%, 93.33%, 98.08% and 98.68%, respectively. Li2CO3 solution recovered from water leaching could be utilised to produce Li2CO3 by evaporative crystallisation. Moreover, divalent solution of Ni, Co and Mn obtained via acid leaching without added reducer could be recycled in the co-precipitation of the ternary precursor. [ABSTRACT FROM AUTHOR]

Abstract As cathode materials for Li-ion batteries (LIBs), V 2 O 5 , possessing a large-spaced and open layered crystal structure, have attracted considerable attention due to their distinct advantages of high specific capacity, abundant raw materials and low cost. Although low-dimensional nanostructured V 2 O 5 can increase the discharge capacity of LIBs, it still suffers from poor cycling and rate performance due to serious self-aggregation and pulverization. Building micro/nano-structures is a highly promising method to address the above issues. Herein, we propose a facile oxidation strategy to successfully synthesize the unique 3D hierarchical porous sponge-like V 2 O 5 micro/nano-structures (V 2 O 5 -SLMNSs) by using the structure-similar sponge-like VO 2 (B)@C micro/nano-structures as a precursor. Importantly, as-synthesized V 2 O 5 -SLMNSs possess the distinct structural advantages of a robust structure with large surface area and abundant meso/micropores, which are beneficial for achieving a better electrochemical performance. Specific capacity during the second discharge for V 2 O 5 -SLMNSs is 232 mAh/g at 100 mA/g, with 87% of the capacity being maintained after 50 cycles, which is considerably higher than the discharge capacity (190 mAh/g) in the second cycle and the value for the capacity retention (69%) of 1D V 2 O 5 nanoribbons. Thus, as-synthesized V 2 O 5 -SLMNSs are promising cathode materials for the next-generation LIBs. Graphical abstract Image 1 Highlights • Unique 3D sponge-like V 2 O 5 micro/nano-structures (V 2 O 5 -SLMNSs) are synthesized. • V 2 O 5 -SLMNSs possess robust structure, large surface area and conductive frameworks. • V 2 O 5 -SLMNSs exhibit the greatly improved electrochemical performance. [ABSTRACT FROM AUTHOR]