Li/Garnet Interface Stabilization by Thermal-Decomposition Vapor Deposition of an Amorphous Carbon Layer.

Applying interlayers is the main strategy to address the large area specific resistance (ASR) of Li/garnet interface. However, studies on eliminating the Li2 CO3 and LiOH interfacial lithiophobic contaminants are still insufficient. Here, thermal-decomposition vapor deposition (TVD) of a carbon modification layer on Li6.75 La3 Zr1.75 Ta0.25 O12 (LLZTO) provides a contaminant-free surface. Owing to the protection of the carbon layer, the air stability of LLZTO is also improved. Moreover, owing to the amorphous structure of the low graphitized carbon (LGC), instant lithiation is achieved, and the ASR of the Li/LLZTO interface is reduced to 9â€…Ω cm2 . Lithium volatilization and Zr4+ reduction are also controllable during TVD. Compared with its high graphitized carbon counterpart (HGC), the LGC-modified Li/LLZTO interface displays a higher critical current density of 1.2 mA cm-2 , as well as moderate Li plating and stripping, which provides enhanced polarization voltage stability.

Designing Carbon Based Supercapacitors with High Energy Density: A Summary of Recent Progress.

Carbon based supercapacitors (CSCs), with high output power and long lifespan, are considered as promising power sources for modern electronic devices. The rush to find new approaches for optimizing their electrochemical behaviors is still vibrant, and particularly, widespread enthusiasm was focused on improving the energy density of CSCs through improving the specific capacitance and expanding the operating voltage. In this regard, this article provides a brief review about recent progress and new understanding about the assembly of CSCs with high energy density. Novel applied strategies were highlighted and discussed from the aspects of electrolyte, electrodes, and device modulation. Dynamic and mechanism factors associated with the energy storage process of CSCs are particularly emphasized. Finally, the opportunities and challenges are elaborated in the hope of guiding the promising direction for the design of high-energy CSCs.

Garnet-Based All-Ceramic Lithium Battery Enabled by Li2.985B0.005OCl Solder.

Garnet-based bulk-type all-ceramic lithium battery (ACLB) is considered to be highly safe, but its electrochemical performance is severely hindered by the huge cathode/electrolyte interfacial resistance. Here, we demonstrate an in situ coated Li2.985B0.005OCl as sintering solder, which is uniformly coated on both LiCoO2 and Li7La3Zr2O12. With the low melting point (267°C) and high ionic conductivity (6.8 × 10-5 S cm-1), the Li2.985B0.005OCl solder not only restricts La/Co interdiffusion, but also provides fast Li+ transportation in the cathode. A low cathode/electrolyte interfacial resistance (386 Ω cm2) is realized owing to the densification of the ACLB by hot-press sintering. The strain/stress of the LiCoO2 is also released by the small elasticity modulus of Li2.985B0.005OCl, leading to a superior cycling stability. The study sheds light on the design of advanced garnet-based bulk-type ACLB by exploring proper solders with higher ionic conductivity, lower melting point, and smaller elasticity modulus.

Oxygen-Vacancy and Surface Modulation of Ultrathin Nickel Cobaltite Nanosheets as a High-Energy Cathode for Advanced Zn-Ion Batteries.

The development of high-capacity, Earth-abundant, and stable cathode materials for robust aqueous Zn-ion batteries is an ongoing challenge. Herein, ultrathin nickel cobaltite (NiCo2 O4 ) nanosheets with enriched oxygen vacancies and surface phosphate ions (P-NiCo2 O4-x ) are reported as a new high-energy-density cathode material for rechargeable Zn-ion batteries. The oxygen-vacancy and surface phosphate-ion modulation are achieved by annealing the pristine NiCo2 O4 nanosheets using a simple phosphating process. Benefiting from the merits of substantially improved electrical conductivity and increased concentration of active sites, the optimized P-NiCo2 O4-x nanosheet electrode delivers remarkable capacity (309.2 mAh g-1 at 6.0 A g-1 ) and extraordinary rate performance (64% capacity retention at 60.4 A g-1 ). Moreover, based on the P-NiCo2 O4-x cathode, our fabricated P-NiCo2 O4-x //Zn battery presents an impressive specific capacity of 361.3 mAh g-1 at the high current density of 3.0 A g-1 in an alkaline electrolyte. Furthermore, extremely high energy density (616.5 Wh kg-1 ) and power density (30.2 kW kg-1 ) are also achieved, which outperforms most of the previously reported aqueous Zn-ion batteries. This ultrafast and high-energy aqueous Zn-ion battery is promising for widespread application to electric vehicles and intelligent devices.

An Ultrastable and High-Performance Flexible Fiber-Shaped Ni-Zn Battery based on a Ni-NiO Heterostructured Nanosheet Cathode.

Currently, the main bottleneck for the widespread application of Ni-Zn batteries is their poor cycling stability as a result of the irreversibility of the Ni-based cathode and dendrite formation of the Zn anode during the charging-discharging processes. Herein, a highly rechargeable, flexible, fiber-shaped Ni-Zn battery with impressive electrochemical performance is rationally demonstrated by employing Ni-NiO heterostructured nanosheets as the cathode. Benefiting from the improved conductivity and enhanced electroactivity of the Ni-NiO heterojunction nanosheet cathode, the as-fabricated fiber-shaped Ni-NiO//Zn battery displays high capacity and admirable rate capability. More importantly, this Ni-NiO//Zn battery shows unprecedented cyclic durability both in aqueous (96.6% capacity retention after 10 000 cycles) and polymer (almost no capacity attenuation after 10 000 cycles at 22.2 A g-1 ) electrolytes. Moreover, a peak energy density of 6.6 µWh cm-2 , together with a remarkable power density of 20.2 mW cm-2 , is achieved by the flexible quasi-solid-state fiber-shaped Ni-NiO//Zn battery, outperforming most reported fiber-shaped energy-storage devices. Such a novel concept of a fiber-shaped Ni-Zn battery with impressive stability will greatly enrich the flexible energy-storage technologies for future portable/wearable electronic applications.