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Novel LiFePO4/Ti3C2 composite (LFP/TC) cathodes have been prepared via a simple wet mixing method followed by a heat treatment at 400 °C. Ti3C2 nanosheets bridge the LiFePO4 nanoparticles to form an integrated conductive network via the “plane-to-point” conducting mode. This conductive network acts as short pathways for the diffusion of both lithium ion and electron in the composite cathode. Thus, the electronic and ionic conductivities are simultaneously enhanced, leading to the improved electrochemical properties of LFP/TC composites. Thereinto, the LFP/TC composite with 2 wt% Ti3C2 (LFP/TC2) delivers the highest initial discharge capacity of 159 mAh g−1 at 0.1 C as well as the best rate performance with a high reversible capacity of 86 mAh g−1 at 5 C. Meanwhile, the LFP/TC2 composite also holds the superior capacity retention of 96% at 1 C after 100 cycles. The results demonstrate that LFP/TC composite has promising practical applications as the cathode material in the high-power lithium-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • HsGDY thin film enhances MnO 2 cathode, enabling high capacity and high-rate performance of ZIBs. • Acetylene bonds in HsGDY facilitate rapid ion transport and enrichment, leading to excellent rate performance. • HsGDY network prevents volume changes and pulverization, ensuring exceptional cycling performance. • Hierarchical pore structure of HsGDY provides additional ion storage active sites, enhancing MnO 2 performance. Conductive layer modification, such as carbon coating layers, has also been widely reported to alleviate the continuous metal ion dissolution and volumetric expansion of rechargeable aqueous zinc-ion batteries (ZIBs) cathode. However, the thick coated layer acts as the inactive material cannot provide enough zinc ion storage sites, reducing the capacity of cathode materials. Here, to address this challenge, we have developed a dressed manganese dioxide nanorods (MnO 2 -NRs) cathode featuring a close-fitting confinement interface constructed from a hydrogen-substituted graphdiyne (HsGDY) thin film (MnO 2 -NRs@HsGDY). The unique hierarchical pore structure and active acetylene bonds of HsGDY film contribute to fast electron/ion transport channel, additional ion storage active site, and structural stability by enriching Zn2+ Sions and confining Mn2+ ions on MnO 2 -NRs surface. The MnO 2 -NRs@HsGDY-based ZIBs exhibit an ultra-high reversible specific capacity of 432 mAh/g under a current density of 50 mA g−1, as well as excellent cyclic stability and superior rate performance. Based on the MnO 2 -NRs@HsGDY, a folding and flexible battery with a high energy density of 162.5 Wh kg−1 at 1 A g−1 can be easily fabricated. Those results demonstrate a straightforward and controllable approach for preparing high-performance cathode materials applied for flexible ZIB. [ABSTRACT FROM AUTHOR]

The multiply depolarized composite cathode consisted of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNCO) and a combinatory conductive network of graphene (GN) + carbon nanotubes (CNTs) in the active material and GN coating at the interface of current collector is synthesized via pasting LMNCO/GN/CNTs composite slurry on GN coated Al foil. The interlaced GN + CNTs conductive network improves both the electronic conductivity and Li ion transport and stabilizes the structure of composite. The GN coating at the interface of current/active materials interlaces with GN + CNTs in the active materials and improves the adhesion and reduces the resistance between the active material and current collector. Consequently, the LMNCO composite cathode exhibits superior rate capacities of 132 mAh g −1 at 5C and 97 mAh g −1 at 10C, high cycling capacity retentions of 86% at 1C and 85% at 2C after 100 cycles, respectively and lower voltage fading. This combinatory conductive network is much more efficient for reducing the resistance and polarization of electrode than any single conductive network of GN + CNTs, CNTs, GN or GN coating. [ABSTRACT FROM AUTHOR]

In this work, double layered LiFePO 4 materials with different content of conductive carbon black are proposed for evaluating systematically the influence of imparity distribution of conductive additive on the electrochemical behaviors of cathode material for lithium ion batteries. Their polarization effects and electrochemical performances were investigated and compared in detail. It was found that there exists a simple empirical rule correlating the distribution of the conductive additive and the depolarization effect under the premise that the total content of the conductive additive is kept constant. The electrochemical performance of LiFePO 4 /C electrode tends to get better with increasing the conductive additive loading in the lower layer. This can be attributed to that the more conductive additive content in the lower layer could provide more available paths for electronic transmission, and markedly decrease the interfacial impedance between LiFePO4/C cathode material and current collector, thus improving the ability of collecting electron and maintaining a reliable electron transport system, especially under high current densities. This finding can enlighten us to design a more rational optimization of the electrode by controlling the distribution of conductive additive in the cathode material for high performance lithium ion batteries. [ABSTRACT FROM AUTHOR]

In this work, three categories of advanced carbon materials coated on current collector are investigated. The results indicate that carbon coating has a positive influence on the depolarization effect and electrochemical performance of LiFePO 4 cathode, different carbon coatings have drastically different influences, high rates in particular. The depolarization effect and rate performance show the following order: Graphene nanosheets (GNs) > Carbon nanotubes (CNTs) > Activated carbons (ACs), and the differences of rate capacities among them become more and more obvious with increasing rates. Especially for 5C, the discharge capacities values are 122 mAh g − 1 , 114.8 mAh g − 1 , 106.8 mAh g − 1 and 49.2 mAh g − 1 for LFP-GNs-Al, LFP-CNTs-Al, LFP-ACs-Al and LFP-Al, respectively. The enhancement is attributed to the carbon coating acting as a transport system of electron between cathode materials and current collector, resulting in reducing the contact impedance within the electrodes, thus providing a favorable balance between fast ion diffusion and increased electron transport. [ABSTRACT FROM AUTHOR]

[Display omitted] • An in situ interfacial film between Li anode and sulfide solid state electrolyte combines the flexibility of organics and denseness of the inorganics. • The modified lithium anode provides inhibition of dendrites growth, enhanced chemical stability. • The batteries equipped with this anode bring high cycle and capacity performance. Sulfide solid electrolytes (SSE) are considered promising alternatives to conventional liquid electrolytes due to their high safety that is inaccessible to common liquid electrolytes and favorable ionic conductivity. Nonetheless, the poor interfacial contacts and stability between SSEs and Li anode, as well as the inhomogeneous dendrite growth severely limit their practical applications. Herein, a trinity artificial solid electrolyte interphase composed of ethyl cellulose, graphene oxide and phosphoric acid was in-situ fabricated on the surface of the Li anode. This Li anode is denoted as EGPL (ethyl-cellulose-graphene-oxide-phosphoric-acid-modified-lithium). The artificial interphase can effectively benefit the uniform deposition of lithium, promote the transport of lithium ions and improve interfacial stability. Therefore, the all-solid-state batteries incorporated with EGPL anode and LiCoO 2 cathode can maintain 94.6% of initial capacity over 100 cycles at 0.2C, and also deliver excellent rate performance. This work provides a novel approach for the interfacial modification of lithium anodes for applications in all-solid-state batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel high-voltage fluorinated electrolyte system is reported. • Our electrolyte can form B- and F-rich inorganic electrode–electrolyte interfaces. • The Li/NCM811 half-cells deliver a high specific capacity (247.2 mAh g−1). • The Gr/NCM811 full-cells show 83.3% of capacity after 100 cycles at 4.6 V. Increasing the operating voltage of Ni-rich cathode materials is a promising route to achieve lithium-ion batteries with a high energy density. However, the unstable electrode–electrolyte interface (EEI) caused by the decomposition of carbonate-based electrolytes at high voltage is a major obstacle. Herein, it is reported that the superior electrochemical performance of the LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) cathode at 4.6 V is achievable using a novel electrolyte system containing fluorinated carbonate and fluorinated carboxylate with a lithium difluoro(oxalate)borate (LiDFOB) additive. The stable B- and F-rich inorganic EEI at high voltage can reduce electrochemical polarization while also preventing the collapse of the cathode structure and continuous dissolution of transition metal ions. As a result, our designed fluorinated electrolyte enables Li/NCM811 half-cells to deliver a high specific capacity (247.2 mAh g−1), superior cyclability (81.4% retention at 200 cycles, 0.5C) and rate performance (154.5 mAh g−1 at 5C) at 4.6 V. The designed electrolyte also enables graphite (Gr)/NCM811 full cells with high loading cathode (≈ 9.5 mg cm−2) to achieve a high capacity retention of 83.3% (0.5C) after 100 cycles at 4.6 V. This work provides a new method to achieve high energy density Gr/NCM811 batteries at high voltage. [ABSTRACT FROM AUTHOR]