Energy-storage technologies, including electrical double-layer capacitors and rechargeable batteries, have attracted significant attention for applications in portable electronic devices, electric vehicles, bulk electricity storage at power stations, and “load leveling” of renewable sources, such as solar energy and wind power. Transforming lithium batteries and electric double-layer capacitors requires a step change in the science underpinning these devices, including the discovery of new materials, new electrochemistry, and an increased understanding of the processes on which the devices depend. The Review will consider some of the current scientific issues underpinning lithium batteries and electric double-layer capacitors.

Challenges Facing Lithium Batteries and Electrical Double‐Layer Capacitors

Recent developments in cathode materials for lithium ion batteries

Due to increasing concerns about global warming, greenhouse gas emissions, and the depletion of fossil fuels, the electric vehicles (EVs) receive massive popularity due to their performances and efficiencies in recent decades. EVs have already been widely accepted in the automotive industries considering the most promising replacements in reducing CO2 emissions and global environmental issues. Lithium-ion batteries have attained huge attention in EVs application due to their lucrative features such as lightweight, fast charging, high energy density, low self-discharge and long lifespan. This paper comprehensively reviews the lithium-ion battery state of charge (SOC) estimation and its management system towards the sustainable future EV applications. The significance of battery management system (BMS) employing lithium-ion batteries is presented, which can guarantee a reliable and safe operation and assess the battery SOC. The review identifies that the SOC is a crucial parameter as it signifies the remaining available energy in a battery that provides an idea about charging/discharging strategies and protect the battery from overcharging/over discharging. It is also observed that the SOC of the existing lithium-ion batteries have a good contribution to run the EVs safely and efficiently with their charging/discharging capabilities. However, they still have some challenges due to their complex electro-chemical reactions, performance degradation and lack of accuracy towards the enhancement of battery performance and life. The classification of the estimation methodologies to estimate SOC focusing with the estimation model/algorithm, benefits, drawbacks and estimation error are extensively reviewed. The review highlights many factors and challenges with possible recommendations for the development of BMS and estimation of SOC in next-generation EV applications. All the highlighted insights of this review will widen the increasing efforts towards the development of the advanced SOC estimation method and energy management system of lithium-ion battery for the future high-tech EV applications.

A review of lithium-ion battery state of charge estimation and management system in electric vehicle applications: Challenges and recommendations

The olivine LiFePO4 now stands as a competitive candidate of cathode material for the next generation of a green and sustainable lithium-ion battery system due to its long life span, abundant resources, low toxicity, and high thermal stability. In this review, we focus on LiFePO4 and discuss its structure, synthesis, electrochemical behavior, mechanism, and the problems encountered in its application. The major goal is to highlight some recent development of LiFePO4 with high rate capability, high energy density, and excellent cyclability resulting from conductive coating, nanocrystallization, or preparation.

Development and challenges of LiFePO4 cathode material for lithium-ion batteries

Battery failure and gradual performance degradation (aging) are the result of complex interrelated phenomena that depend on battery chemistry, design, environment, and the actual operation conditions. The current available knowledge on these matters results from a vast combination of experimental and modeling approaches. We explore the state of the art with respect to materials as well as usage (temperature, charge/discharge rate, etc.) for lead-acid, nickel-cadmium, nickel-metal hydride, and lithium-ion chemistries. Battery diagnosis strategies and plausible developments related to large-scale battery applications are also discussed.

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Why do batteries fail

Identifying battery aging mechanisms in large format Li ion cells

Preparation and characterization of Ti4+-doped LiFePO4 cathode materials for lithium-ion batteries

Effects of vanadium substitution on the cycling performance of olivine cathode materials

In this study, Li3V2(1-x)Fe3x(PO4)3 (0 ≤ x ≤ 0.09) powders are prepared via a solution method and heattreated at 700 °C for 8 hours. The chemical composition, morphology, crystalline structure, and valence of iron in the prepared samples were investigated with ICP, SEM, XRD, and EXAFS. The effects of Fe-substitution for vanadium sites on the electrochemical properties as cathode materials for lithium ion batteries are studied with capacity retention study and incremental capacity analysis. In addition to the monoclinic Li3V2(PO4)3 phase, olivine LiFePO4 is also observed when x ≥ 0.03. The valence of iron in the prepared powders is predominately 3+ at low substitution level (x ≤ 0.05), while the ratio of the Fe2+ to Fe3+ increases abruptly when the substitution level is higher than x = 0.07. Among the prepared samples, Li3V1.86Fe0.21(PO4)3 shows the best cycling performance at rates higher than 1C. It demonstrates discharge capacities of 141.2 mAh/g for second cycle and 126 mAh/g after 30 cycles at 5C rate.

Mao-Sung Chen

Papers

Identifying battery aging mechanisms in large format Li ion cells

Preparation and characterization of Ti4+-doped LiFePO4 cathode materials for lithium-ion batteries

Effects of vanadium substitution on the cycling performance of olivine cathode materials

Preparation and Characterization of Fe-substituted Li3V2(PO4)3 Cathodes for Li-ion Batteries