Mitigating the Surface Reconstruction of Ni-Rich Cathode via P2-Type Mn-Rich Oxide Coating for Durable Lithium Ion Batteries

Amphiphilic Polymer Electrolyte Blocking Lattice Oxygen Evolution from High-Voltage Nickel-rich Cathodes for Ultra-Thermal Stabile Batteries

Ni-rich cathodes have been intensively adopted in Li-ion batteries to pursuit high energy density, which still suffering irreversible degradation at high voltage. Some unstable lattice O2- species in Ni-rich cathodes would be oxidized to singlet oxygen 1O2 and released at high volt, which lead to irreversible phase transfer from the layered rhombohedral (R) phase to a spinel-like (S) phase. To overcome the issue, the amphiphilic copolymers (UMA-Fx) electrolyte were prepared by linking hydrophobic C-F side chains with hydrophilic subunits, which could self-assemble on Ni-rich cathode surface and convert to stable cathode-electrolyte interphase layer. Thereafter, the oxygen releasing of polymer coated cathode was obviously depressed and substituted by the Co oxidation (Co3+→Co4+) at high volt (>4.2 V), which could suppressed irreversible phase transfer and improve cycling stability. Moreover, the amphiphilic polymer electrolyte was also stable with Li anode and had high ion conductivity. Therefore, the NCM811//UMA-F6//Li pouch cell exhibited outstanding energy density (362.97 Wh/kg) and durability (cycled 200 times at 4.7 V), which could be stalely cycled even at 120°C without short circuits or explosions.

Ni-Rich Layered Oxide Cathodes/Sulfide Electrolyte Interface in Solid-State Lithium Battery

Because of the high specific capacity and low cost, Ni-rich layered oxide (NRLO) cathodes are one of the most promising cathode candidates for the next high-energy-density lithium-ion batteries. However, they face structure and interface instability challenges, especially the battery safety risk caused by using an intrinsic flammable organic liquid electrolyte. In this regard, a solid electrolyte with high safety is of great significance to promote the development of energy storage. Among them, sulfide electrolytes are considered to be the most potential substitutes for liquid electrolytes because of their high ionic conductivity and good processing properties. Nevertheless, the interfacial incompatibility between the sulfide electrolyte and NRLO cathode is the critical challenge for high-performance sulfide all-solid-state lithium batteries (ASSLBs). In this review, we summarize the problems of the Ni-rich cathode/sulfide solid electrolyte interface and the strategies to improve the interface stability. On the basis of these insights, we highlight the scientific problems and technological challenges that need to be resolved urgently and propose several potential directions to further improve the interface stability. The objective of this study is to provide a comprehensive understanding and insightful recommendations for the enhancement of the sulfide ASSLBs with NRLO cathode.

Lithiophilic and Eco-Friendly Nano-Se Seeds Unlock Dendrite-Free and Anode-Free Li-Metal Batteries

A 3D host design for lithium (Li)-metal anodes can effectively accommodate volume changes and suppress Li dendrite growth; nonetheless, its practical applicability in energy-dense Li-metal batteries (LMBs) is plagued by excessive Li loading. Herein, we introduced eco- and human-friendly Se seeds into 3D carbon cloth (CC) to create a robust host for efficient Li deposition/stripping. The highly lithiophilic nano-Se endowed the Se-decorated CC (Se@CC) with perfect Li wettability for instantaneous Li infusion. At an optimal Li loading of 17 mg, the electrode delivered an unprecedentedly long life span of 5400 h with low overpotentials <36 mV at 1 mA cm-2/1 mAh cm-2 and 1500 h at 5 mA cm-2/5 mAh cm-2. Furthermore, the uniform Se distribution and strong Li-Se binding allowed for further reduction in Li loading to 2 mg via direct Li electrodeposition. The corresponding LiNi0.8Co0.1Mn0.1O2 (NCM811)-based full cell afforded a high capacity retention rate of 74.67% over 300 cycles at a low N/P ratio of 8.64. Finally, the initial anode-free LMB using a NCM811 cathode and a Se@CC anode current collector demonstrated a high electrode-level specific energy of 531 Wh kg-1 and consistently high CEs >99.7% over 200 cycles. This work highlights a high-performance host design with excellent tunability for practical high-energy-density LMBs.