Commercial Prospects of Existing Cathode Materials for Sodium Ion Storage

Abstract

Transition Metal Oxides (Na x MO 2 , x ≤ 1, M = Transition Metal)Transition metal oxides Na x MO 2 , (x ≤ 1, M = transition metal, Co, Mn, Fe, Ni, etc.) have recently received increased attention due to their high energy density, above 400 W h kg −1 . [69,75,76] Moreover, its lithium counterpart-Li x MO 2 has been successfully applied in commercial LIBs. Generally speaking, Na x MO 2 can Sodium ion batteries (SIBs) have recently attracted considerable attention and are considered as an alternative to lithium ion batteries (LIBs), owing to the cheap price and abundance of sodium resources. However, the commercialization of SIBs has so far been impeded by the low energy density and unstable cycle life of electrodes, especially as cathodes. Although some cathode candidates with a stable cycle life and high energy density have been developed using nanotechnologies, the commercial feasibility is seldom taken into account. This research news article provides an insight into the commercial prospects of existing cathode materials for SIBs in terms of environmental friendliness, manufacturing cost, synthesis methods and electrochemical performance. Sodium Ion Batteries IntroductionRecently, owing to the ever-increasing consumption of lithium resources, the price of lithium ion batteries (LIBs) has increased rapidly. As researchers strive to seek an alternative to LIBs for energy storage, sodium ion batteries (SIBs) have been attracting more attention due to their similar electrochemical properties to LIBs and low cost. The major challenge for SIB commercialization is the low energy density and unstable cycle life of electrode materials. The energy density is related to the capacity and potential plateau.A wide variety of materials have been investigated as electrode materials for SIBs. Anode candidates, include carbonaceous materials, [26][27][28][29][30][31][32][33][34][35][36] alloy-forming elements (Sn, Sb, Ge and P), and alloy compound (SnSb, phosphide, et al). [59,60,[63][64][65] Moreover, the current anode candidates can deliver more than 200 mA h g −1 capacity, and most of them can show stable cycle life more than 200 cycles through various strategies of structural modification and nanotechnology. Reported cathode materials candidates can be divided into four classes: transition metal (M) oxides (Na x MO 2+y ), [8][9][10][11] Adv. Energy

Stress Distortion Restraint to Boost the Sodium Ion Storage Performance of a Novel Binary Hexacyanoferrate

“…The Fe-based hexacyanoferrate Na x FeFe(CN) 6 has shown excellent stable cycle life, but it presents both a low voltage plateau at 3.0 V and low capacity around 100 mAh g −1 . Renewable forms of energy, such as wind and solar energy, however, are intermittent due to weather variation.…”

“…Moreover, the synthetic method used is a semi-hydrothermal method, which is not suitable for commercial application due to low product yield. [28,30] One hypothesis is proposed that the Na x MnFe(CN) 6 framework could be stabilized and that the compound could simultaneously possess a higher voltage plateau if the Mn 2+ could be selectively removed while maintaining the Mn 3+ via introducing a second transition metal (T, T = Fe, Co, Ni, Cu, V; 0 < x < 1). The Na-rich NMHFC (x > 1.40) shows an especially high energy density with large capacity of 125 mAh g −1 .…”

“…Herein, a series of binary hexacyanoferrates with the formula Na x Fe y Mn 1−y Fe(CN) 6 (denoted as NMFHFC, 0 < x < 2, 0 < y < 1) have been synthesized and their electrochemical performance tested as cathodes for sodium-ion storage for the first time, with special consideration of their environmental friendliness (Fe and Mn elements) and commercial prospects. In this work, the Fe/Mn-based binary hexacyanoferrate NMFHFC has been developed through a facile and energy-efficient coprecipitation method for the first time.…”

“…[1][2][3][4][5][6][7][8][9][10][11] Hitherto, the commercialization of SIBs has been held back, however, by their low energy density and unsatisfactory cycle life. [1][2][3][4][5][6][7][8][9][10][11] Hitherto, the commercialization of SIBs has been held back, however, by their low energy density and unsatisfactory cycle life.…”

“…[6,[25][26][27][28] The PBAs utilized for electrode materials can be classified into three groups, that is, hexacyanoferrates (ATFe(CN) 6 ), hexacyanomanganates (ATMn(CN) 6 ), and hexacyanocobaltates (ATCo(CN) 6 , where A = K, Na; T = Fe, Mn, Ni, Co). [6,[25][26][27][28] The PBAs utilized for electrode materials can be classified into three groups, that is, hexacyanoferrates (ATFe(CN) 6 ), hexacyanomanganates (ATMn(CN) 6 ), and hexacyanocobaltates (ATCo(CN) 6 , where A = K, Na; T = Fe, Mn, Ni, Co).…”