Electrolyte formulation strategies for potassium‐based batteries

Abstract

Potassium (K)-based batteries are viewed as the most promising alternatives to lithiumbased batteries, owing to their abundant potassium resource, lower redox potentials (−2.97 V vs. SHE), and low cost. Recently, significant achievements on electrode materials have boosted the development of potassium-based batteries. However, the poor interfacial compatibility between electrode and electrolyte hinders their practical. Hence, rational design of electrolyte/electrode interface by electrolytes is the key to develop K-based batteries. In this review, the principles for formulating organic electrolytes are comprehensively summarized. Then, recent progress of various liquid organic and solidstate K + electrolytes for potassium-ion batteries and beyond are discussed. Finally, we offer the current challenges that need to be addressed for advanced K-based batteries. K E Y WO R D Sfundamentals of organic electrolytes, liquid electrolytes, potassium-based batteries, solid-state electrolytes This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Weak Solvent–Solvent Interaction Enables High Stability of Battery Electrolyte

“…Then, varying the interactions of M + –solvent, M + –anion pair, and anion–solvent by changing the type and quantity of solvents, anions, additives, etc., have received significant attention recently to tune the electrolyte properties. − It is worth noting that solvent–solvent interaction has rarely been mentioned before, as such interaction is considered to be very weak, 1–2 orders of magnitude weaker than the ion–ion interaction between M + –anion and the ion-dipole interaction between M + –solvent . However, it is still necessary to make clear the effect of solvent–solvent interactions, as the molar quantity of solvent in the commercial electrolyte is always 10–12 times higher than that of cation and anion when electrolyte with a concentration of 1 M was used. − Therefore, whether the strength of this weak solvent–solvent interaction is sufficient to affect the performance of the electrolyte needs to be paid attention to.…”

Engineering Electrode/Electrolyte Interphase Chemistry toward High-Rate and Long-Life Potassium Ion Full-Cell

“…The depth-profiling XPS analysis indicates that the main variation of SEI compositions occurs in the outer layer. Specifically, the O 1s spectra of the Gr-0.01 V anode retrieved from KFeHCF (4.5 V)/Gr (0.01 V) and obtained at 0 s sputtering time show decreased PEDC (potassium ethylene decarbonate, (CH 2 OCO 2 K) 2 ) content (which is decomposed into K 2 CO 3 , Figure i) and increased PEO (poly­(ethylene oxide) oligomers, −(CH 2 CH 2 O) n −) content (attributed to the decomposition of EC solvent, Figure j) after cycling. , Meanwhile, its F 1s spectra collected at 0 s sputtering time exhibit decreased the K x PF y O z content, which is found to be decomposed into KF. ,, In contrast, for the Gr-3.0 V anode retrieved from KFeHCF (2.0 V)/Gr (3.0 V), the contents of PEDC and K x PF y O z increased while that of PEO decreased after cycling, which is likely due to the decomposition of EC and KPF 6 to generate PEDC and K x PF y O z , respectively . The presence and uniform distribution of K 2 CO 3 in the SEI in KFeHCF (4.5 V)/Gr (0.01 V) was also identified by the Raman mapping and XRD results (Figure S16).…”

Reclaiming Neglected Compounds as Promising Solid State Electrolytes by Predicting Electrochemical Stability Window with Dynamically Determined Decomposition Pathway

“…G A 0 is the Gibbs free energy of one A atom in the reference state, namely metallic A. Δ r G is the driving force for the electrochemical decomposition reaction. [52,53] Given the fact that the electric potential Φ is a function of x as determined in A x M y N z , the relationship between Δ r G and Φ can be represented following eqn (5):…”

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major obstacles in the development of all-solid-state batteries (ASSBs) with high energy density, high intrinsic safety, and long service life. [1][2][3][4][5] Compared with modification (such as doping, [6,7] coating [8][9][10][11][12] ) on well-known SSEs, high-throughput screenings on less-investigated candidate materials with high ion conductivities and wide ESWs can provide a much larger database for SSE selection, thereby tremendously accelerating the development of ASSBs. [13][14][15][16] Recently, the rapid development of materials databases (e.g., Materials Project, [17] Inorganic Crystal Structure Database [18,19] ) has enabled the possibility for such high-throughput screenings.

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