Designing 3D Anode Based on Pore-Size-Dependent Li Deposition Behavior for Reversible Li-Free All-Solid-State Batteries

Two-dimensional LiTi2(PO4)3 flakes for enhanced lithium ions battery anode

In this work, the LiTi2(PO4)3 (LTP) flakes have been prepared by employing a template method for lithium-ion batteries with high capacity. The 2D layered structure of LTP offers large aspect ratio and rich active sites, which not only create the large contact area between the electrolyte and electrode, but also promote the diffusion kinetics of Li+. As a result, the Li+ diffusion coefficient of lamellar LTP anode is 3.12 × 10-8 cm2 s-1, while it is only 5.01 × 10-10 cm2 s-1 for granular LTP anode. Further, the lamellar LTP anode delivers a high initial discharge capacity of 986.8 mAh·g-1 at 0.1 A g-1, and remains at 231.1 mAh·g-1 after 100 cycles, which is higher than that of the granular LTP anode (340.5 mAh·g-1 at 1st cycle, 169.3 mAh·g-1 at 100th cycles). Thus, the lamellar LTP should be recommended as a potential anode for high-performance LIBs due to the fast charge-discharge performance and superior cycling stability.

Design Strategies for Anodes and Interfaces Toward Practical Solid-State Li-Metal Batteries

Solid-state Li-metal batteries (based on solid-state electrolytes) offer excellent safety and exhibit high potential to overcome the energy-density limitations of current Li-ion batteries, making them suitable candidates for the rapidly developing fields of electric vehicles and energy-storage systems. However, establishing close solid-solid contact is challenging, and Li-dendrite formation in solid-state electrolytes at high current densities causes fatal technical problems (due to high interfacial resistance and short-circuit failure). The Li metal/solid electrolyte interfacial properties significantly influence the kinetics of Li-metal batteries and short-circuit formation. This review discusses various strategies for introducing anode interlayers, from the perspective of reducing the interfacial resistance and preventing short-circuit formation. In addition, 3D anode structural-design strategies are discussed to alleviate the stress caused by volume changes during charging and discharging. This review highlights the importance of comprehensive anode/electrolyte interface control and anode design strategies that reduce the interfacial resistance, hinder short-circuit formation, and facilitate stress relief for developing Li-metal batteries with commercial-level performance.

All-Solid-State Batteries with Pre-plated Ultrathin Lithium Metal Enabled by No Pressure Holding and Characterized by In Situ Electron Paramagnetic Resonance Imaging

All-solid-state batteries with ultrathin lithium metal, close to the anode-free solid-state batteries, could achieve high energy density. However, it is not trivial to plate an ultrathin lithium metal layer on a Cu current collector (Cu-CC). In situ electron paramagnetic resonance (EPR) imaging showed that the pre-plating on Cu-CC in a Li-In|Li₆PS₅Cl|Cu cell without pressure holding produced a lithium metal layer with a small area. However, when a Li-In|Li₆PS₅Cl|Cu cell was held under a considerable pressure, this cell would produce a lithium metal layer with a large area. The Cu-CC with the ultrathin lithium metal layer of a small surface could be extracted and then assembled with LiNiO₂ and Li₆PS₅Cl to achieve better electrochemical performance compared to that of a large surface, because a small area of the lithium metal layer would lead to fewer side reactions and less consumption of lithium ions. This work suggests the importance of the control of the lithium plating and the observation of lithium plating by in situ EPR imaging.