Search

Lithium‐ion batteries (LIBs) suffer from energy loss and safety hazards under high‐rate conditions, because of the sluggish electrochemical kinetics and unstable interfacial passivation. Herein, a PC‐based electrolyte using weakly solvated solvent ethyl trifluoroacetate is developed to improve interfacial kinetics and stability in LIBs. A microsolvating competition is revealed in the bulk electrolyte, forming a loose Li+ coordination configuration with benign Li+ affinity and high ionic conductivity. Furthermore, an inorganic‐rich interphase is constructed on a graphite anode, affording smooth Li+ desolvation and reliable passivation. Consequently, the NCM622/graphite cell in PC‐based electrolyte shows improved cycling stability (82.2% after 200 cycles) and rate capability (83% at 4C compared to 0.1C) at a high‐voltage of 4.5 V, much better than those of EC‐based electrolyte (76.2% after 200 cycles and 74% at 4C). Additionally, the PC‐based electrolyte affords reversible operation at –40 °C while the EC‐based electrolyte fails at –40 °C. This work highlights the potential of solvation structure engineering for low‐energy‐barrier electrolyte. [ABSTRACT FROM AUTHOR]

Ni−rich cathodes are hopeful materials for advanced lithium−ion batteries (LIBs) due to high capacity. Nonetheless, the chemical crosstalk triggered by reactive oxygen (O*) represents a critical factor in thermal runaway (TR). Currently, there are few effective means to prevent this parasitic reaction. Here, inspired by the O* scavenging effect of β−carotene in living organisms, it is innovatively identified that β−carotene can impede TR by restraining the escape of O* during the thermal decomposition of nickel−rich cathodes. Using LiNi0.6Co0.2Mn0.2O2 as model and extending to higher nickel content cathodes (LiNi0.8Co0.1Mn0.1O2, LiNi0.9Co0.05Mn0.05O2), it is demonstrated that β−carotene can undergo an in situ oxygen copolymerization reaction to trapping O*, thereby attenuating chemical crosstalk. Additionally, the generated oxygen copolymer can also adjust band center of the O 2p orbitals of delithiated cathode, alleviating the charge compensation behavior of oxygen anions, and thus delaying the phase transition of charged LiNi0.8Co0.1Mn0.1O2. As a result, the TR trigger temperature of NCM811∣Graphite pouch cell is increased from 131.0 to 195.0 °C and maximum temperature is reduced from 657.8 to 412.4 °C. This work introduces a new and simple strategy for designing functional additives to block TR, offering a promising avenue for advancing the safety of LIBs. [ABSTRACT FROM AUTHOR]

In recent years, recycling of numerous spent lithium-ion battery cathode materials has received increasing attention in order to protect the environment as well as to conserve resources, and the recovery of spent LiFePO4 (LFP) by direct regeneration has been widely studied. A considerable body of literature has delved into the failure mechanism of LFP. The mechanism is characterized by an irreversible phase change, which is primarily attributed to the sluggish diffusion of lithium ions (Li+) during cycling. Additionally, the migration of iron (Fe) ions to occupy Li+ sites further impedes Li+ diffusion. Consequently, the electrochemical performance of directly regenerated LFP is diminished by the phenomenon of Li defects. Here, a method of direct regeneration of LFP based on a doping strategy using environmentally friendly and economically efficient natural biomass amino acids has been developed, which inhibits Fe ion migration and improves the diffusion kinetics of Li+ and electrons by constructing a nitrogen-doped carbon coating. The regenerated LFP cathode exhibits excellent cycling stability and rate performance (98.7% capacity retention over 100 cycles at 1C current density and a high capacity retention of 87.9% after 500 cycles at 1C). [ABSTRACT FROM AUTHOR]

Compared to traditional lithium‐ion batteries with liquid electrolytes, all‐solid‐state lithium batteries have attracted extensive attention due to their heightened safety and energy density. Lithium argyrodite materials are promising solid electrolytes (SE) due to their high ionic conductivity, low grain boundary resistance, and favorable mechanical properties. However, the poor chemical/electrochemical stability of lithium argyrodite electrolytes toward the bare lithium metal anode inhibits their applications in all‐solid‐state lithium metal batteries (ASSLMBs). Here, Li‐SnF2 composite anodeswas used to induce the formation of solid electrolyte interphase (SEI) composed of LiCl, LiF, and Li22Sn5 at the Li/SE interface. The high interface energy barriers for LiF and LiCl induces the uniform deposition of lithium ions, thus hindering the growth of lithium dendrites. Meanwhile, the fast Li‐ion diffusion coefficient of the Li22Sn5 alloy accelerates Li‐ion migration across the interface section. The symmetrical cell exhibits stable cycling performance over long durations over 300 h at 0.5 mA cm−2. Moreover, the LiNbO3@NCM712/Li5.5PS4.5Cl1.5/Li‐10%SnF2 battery delivers a high initial discharge capacity of 170.9 mAh g−1 at 0.1C and retains 72.9% of its original capacity after 500 cycles at 0.5C. The facial approach for Li‐SnF2 composite anode enables the production of ASSLMBs with superior electrochemical performance. [ABSTRACT FROM AUTHOR]