Yes. If you can't access fastboot and the OS, you need to use the Emergence Download Mode (EDL) for you phone (volume down + power).
XDA forums has all the steps and guides to unbrick your device.
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Download your firmware file (please check your SoC due to the different phone variants).
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Download and compile the QDL tool with some more details about QDL here.
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Enter EDL mode.
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Flash your firmware as described by the first link in step 2.
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Profit????
Sodium batteries seem promising, though density is lower than Lithium.