considered as a promising alternative to graphite anode, the energy density of Li 4 Ti 5 O 12 is severely limited by its low theoretical specific capacity (175 mAh g -1 ) and high lithiation potential (1.5 V vs Li + / Li) [4][5][6][7] . Low lithiation potential (0.2 V vs Li + /Li) of silicon anode with the highest specific capacity (3579 mAh g -1 ) could inevitably result in serious lithium dendrites in fast charging process. [8][9][10][11] Phosphorus with a high theoretical specific capacity (2596 mAh g -1 ) and suitable lithiation potential (0.7 V vs Li + /Li) is an ideal anode material with high-energy density and fast-charging capability [1][2][3] (Figure 1a). However, the high-rate capability of P anode is hindered by its low electronic (≈10 −12 S m -1 ) and sluggish lithiation reaction kinetics that are two important influencing factors for fast-charging electrode. In addition, the unstable solidelectrolyte interphase (SEI) is due to the side reactions at the interface of electrode and electrolyte as well as the large volume expansion (≈300%) of P upon lithiation, what is worse, the dissolution behavior of intermediates (lithium polyphosphides, Li x Ps) results in low Coulombic efficiency and continual capacity fading, impairing the long-cycling stability. [12,13] To solve these problems, various carbon carriers and conductive polymer coating layers are usually introduced into P anode. [1][2][3][14][15][16][17][18] However, high Li diffusion barriers in carbon-based frameworks (0.34 eV) [19] and the heterogeneous interface, respectively, hinder the superior fastcharging performance of P-based composites. In addition, the problem of uneven local reaction in P particles has not been solved yet.Herein, to enhance the fast-charging performance, we introduced electrochemically active bismuth, a 2D layered material with a layer spacing of 0.396 nm, [20,21] into P/graphite (P/C) composite as a functional filler by the ball-milling method. Bi works as an anode with a similar electrochemical-reaction potential range as P anode, but the starting lithiation/delithiation potential is a little bit higher/lower than the latter, respectively. Besides, Bi anode offers excellent Li-ion diffusion and electron transport capability, combined with the strong interaction at interface of Bi and P, which can promote both Li ion and electron transport at the interface between Bi and P anode. Thus, Bi can work as a small Li reservoir for trapping Li in lithiation process and emitting Li in delithiation process prior to P Phosphorus anodes are a promising for fast-charging high-energy lithium-ion batteries because of their high specific capacity (2596 mAh g -1 ) and suitable lithiation potential (0.7 V vs Li + /Li). To solve the large volumetric change and inherent poor electrical conductivity, various carbon-based materials have been studied for loading P. However, the local aggregation of Li ions and electrons in P particles especially in the fast-charging process induces an uneven lithiation reaction and the great transient stress...
Metal-doped cobalt spinel oxides are considered to be effective materials to improve the oxygen reduction reaction (ORR) performance. However, the doping sites of nickel in Co3O4 spinel (octahedral sites or tetrahedral sites) remain controversial, leading to a poor understanding of the effects of nickel. Herein, directionally introducing nickel into the octahedral sites of Co3O4 (Ni Oh -Co3O4) is proposed by exploiting the different redox capabilities of different nickel sources, which yields an encouraging ORR and rechargeable Zn–air battery performance. Magnetic measurements and theoretical calculations reveal that the nickel occupied at the octahedral site can effectively promote the spin-state transition from low spin to higher spin states for cobalt ions and the hybridization of Co 3d–O 2p electrons, resulting in the optimization of the adsorption strength for the oxygen intermediates, thus improving the oxygen catalytic activity of Ni Oh -Co3O4.
Li‐Ion Batteries In article number 2103888, Jie Sun and co‐workers report the development of a Bi anode that works as a small Li reservoir for trapping/emitting Li in lithiation/delithiation processes prior to that of the P anode. Nezha, a protection deity in Chinese folk religion, defeated the Dragon King who caused the flood. Similarly, Bi promotes fast and uniform lithiation/delithiation reactions and avoids continuous cracking of the Bi‐P/C electrode.
Local Electric Field In article number 2208514, Jie Sun and co‐workers report the development of a local electric field by constructing ionic covalent organic frameworks to comprehensively solve the problems of the phosphorus anode. These multifunctional facets are mainly embodied in inhibiting the dissolution of intermediates, promoting the reaction kinetics, and regulating the solid electrolyte interphase, and the obtained phosporus anode demonstrates favorable performance for lithium‐ion batteries.
High‐capacity Ni‐rich layered oxides are considered as promising cathodes for lithium‐ion batteries. However, the practical applications of LiNi0.83Co0.07Mn0.1O2 (NCM83) cathode are challenged by continuous transition metal (TM) dissolution, microcracks and mixed arrangement of nickel and lithium sites, which are usually induced by deleterious cathode–electrolyte reactions. Herein, it is reported that those side reactions are limited by a reliable cathode electrolyte interface (CEI) layer formed by implanting a nonsacrificial nitrile additive. In this modified electrolyte, 1,3,6‐Hexanetricarbonitrile (HTCN) plays a nonsacrificial role in modifying the composition, thickness, and formation mechanism of the CEI layers toward improved cycling stability. It is revealed that HTCN and 1,2‐Bis(2‐cyanoethoxy)ethane (DENE) are inclined to coordinate with the TM. HTCN can stably anchor on the NCM83 surface as a reliable CEI framework, in contrast, the prior decomposition of DENE additives will damage the CEI layer. As a result, the NCM83/graphite full cells with the LiPF6‐EC/DEC‐HTCN (BE‐HTCN) electrolyte deliver a high capacity retention of 81.42% at 1 C after 300 cycles at a cutoff voltage of 4.5 V, whereas BE and BE‐DENE electrolytes only deliver 64.01% and 60.05%. This nonsacrificial nitrile additive manipulation provides valuable guidance for developing aggressive high‐capacity Ni‐rich cathodes.
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